SkImageFilters Class Reference

#include <SkImageFilters.h>

Classes
struct	CropRect

Public Types
enum class	Dither : bool { kNo = false , kYes = true }

Static Public Member Functions
static sk_sp< SkImageFilter >	Arithmetic (SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4, bool enforcePMColor, sk_sp< SkImageFilter > background, sk_sp< SkImageFilter > foreground, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Blend (SkBlendMode mode, sk_sp< SkImageFilter > background, sk_sp< SkImageFilter > foreground=nullptr, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Blend (sk_sp< SkBlender > blender, sk_sp< SkImageFilter > background, sk_sp< SkImageFilter > foreground=nullptr, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Blur (SkScalar sigmaX, SkScalar sigmaY, SkTileMode tileMode, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Blur (SkScalar sigmaX, SkScalar sigmaY, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	ColorFilter (sk_sp< SkColorFilter > cf, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Compose (sk_sp< SkImageFilter > outer, sk_sp< SkImageFilter > inner)
static sk_sp< SkImageFilter >	Crop (const SkRect &rect, SkTileMode tileMode, sk_sp< SkImageFilter > input)
static sk_sp< SkImageFilter >	Crop (const SkRect &rect, sk_sp< SkImageFilter > input)
static sk_sp< SkImageFilter >	DisplacementMap (SkColorChannel xChannelSelector, SkColorChannel yChannelSelector, SkScalar scale, sk_sp< SkImageFilter > displacement, sk_sp< SkImageFilter > color, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	DropShadow (SkScalar dx, SkScalar dy, SkScalar sigmaX, SkScalar sigmaY, SkColor color, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	DropShadowOnly (SkScalar dx, SkScalar dy, SkScalar sigmaX, SkScalar sigmaY, SkColor color, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Empty ()
static sk_sp< SkImageFilter >	Image (sk_sp< SkImage > image, const SkRect &srcRect, const SkRect &dstRect, const SkSamplingOptions &sampling)
static sk_sp< SkImageFilter >	Image (sk_sp< SkImage > image, const SkSamplingOptions &sampling)
static sk_sp< SkImageFilter >	Magnifier (const SkRect &lensBounds, SkScalar zoomAmount, SkScalar inset, const SkSamplingOptions &sampling, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	MatrixConvolution (const SkISize &kernelSize, const SkScalar kernel[], SkScalar gain, SkScalar bias, const SkIPoint &kernelOffset, SkTileMode tileMode, bool convolveAlpha, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	MatrixTransform (const SkMatrix &matrix, const SkSamplingOptions &sampling, sk_sp< SkImageFilter > input)
static sk_sp< SkImageFilter >	Merge (sk_sp< SkImageFilter > *const filters, int count, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Merge (sk_sp< SkImageFilter > first, sk_sp< SkImageFilter > second, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Offset (SkScalar dx, SkScalar dy, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Picture (sk_sp< SkPicture > pic, const SkRect &targetRect)
static sk_sp< SkImageFilter >	Picture (sk_sp< SkPicture > pic)
static sk_sp< SkImageFilter >	RuntimeShader (const SkRuntimeShaderBuilder &builder, std::string_view childShaderName, sk_sp< SkImageFilter > input)
static sk_sp< SkImageFilter >	RuntimeShader (const SkRuntimeShaderBuilder &builder, SkScalar sampleRadius, std::string_view childShaderName, sk_sp< SkImageFilter > input)
static sk_sp< SkImageFilter >	RuntimeShader (const SkRuntimeShaderBuilder &builder, std::string_view childShaderNames[], const sk_sp< SkImageFilter > inputs[], int inputCount)
static sk_sp< SkImageFilter >	RuntimeShader (const SkRuntimeShaderBuilder &builder, SkScalar maxSampleRadius, std::string_view childShaderNames[], const sk_sp< SkImageFilter > inputs[], int inputCount)
static sk_sp< SkImageFilter >	Shader (sk_sp< SkShader > shader, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Shader (sk_sp< SkShader > shader, Dither dither, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Tile (const SkRect &src, const SkRect &dst, sk_sp< SkImageFilter > input)
static sk_sp< SkImageFilter >	Dilate (SkScalar radiusX, SkScalar radiusY, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	Erode (SkScalar radiusX, SkScalar radiusY, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	DistantLitDiffuse (const SkPoint3 &direction, SkColor lightColor, SkScalar surfaceScale, SkScalar kd, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	PointLitDiffuse (const SkPoint3 &location, SkColor lightColor, SkScalar surfaceScale, SkScalar kd, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	SpotLitDiffuse (const SkPoint3 &location, const SkPoint3 &target, SkScalar falloffExponent, SkScalar cutoffAngle, SkColor lightColor, SkScalar surfaceScale, SkScalar kd, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	DistantLitSpecular (const SkPoint3 &direction, SkColor lightColor, SkScalar surfaceScale, SkScalar ks, SkScalar shininess, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	PointLitSpecular (const SkPoint3 &location, SkColor lightColor, SkScalar surfaceScale, SkScalar ks, SkScalar shininess, sk_sp< SkImageFilter > input, const CropRect &cropRect={})
static sk_sp< SkImageFilter >	SpotLitSpecular (const SkPoint3 &location, const SkPoint3 &target, SkScalar falloffExponent, SkScalar cutoffAngle, SkColor lightColor, SkScalar surfaceScale, SkScalar ks, SkScalar shininess, sk_sp< SkImageFilter > input, const CropRect &cropRect={})

Detailed Description

Definition at line 42 of file SkImageFilters.h.

Member Enumeration Documentation

Dither

enum class SkImageFilters::Dither : bool

strong

Enumerator
kNo
kYes

Definition at line 438 of file SkImageFilters.h.

                      : bool {
        kNo = false,
        kYes = true
    };

Member Function Documentation

Arithmetic()

sk_sp< SkImageFilter > SkImageFilters::Arithmetic ( SkScalar  k1, SkScalar  k2, SkScalar  k3, SkScalar  k4, bool  enforcePMColor, sk_sp< SkImageFilter >  background, sk_sp< SkImageFilter >  foreground, const CropRect &  cropRect = {}  )

static

Create a filter that implements a custom blend mode. Each output pixel is the result of combining the corresponding background and foreground pixels using the 4 coefficients: k1 * foreground * background + k2 * foreground + k3 * background + k4

Parameters

k1,k2,k3,k4	The four coefficients used to combine the foreground and background.
enforcePMColor	If true, the RGB channels will be clamped to the calculated alpha.
background	The background content, using the source bitmap when this is null.
foreground	The foreground content, using the source bitmap when this is null.
cropRect	Optional rectangle that crops the inputs and output.

Definition at line 151 of file SkBlendImageFilter.cpp.

                                                                          {
    auto blender = SkBlenders::Arithmetic(k1, k2, k3, k4, enforcePMColor);
    if (!blender) {
        // Arithmetic() returns null on an error, not to optimize src-over
        return nullptr;
    }
    return make_blend(std::move(blender),
                      std::move(background),
                      std::move(foreground),
                      cropRect,
                      // Carry arithmetic coefficients and premul behavior into image filter for
                      // serialization and bounds analysis
                      SkV4{k1, k2, k3, k4},
                      enforcePMColor);
}

Blend() [1/2]

sk_sp< SkImageFilter > SkImageFilters::Blend ( sk_sp< SkBlender >  blender, sk_sp< SkImageFilter >  background, sk_sp< SkImageFilter >  foreground = nullptr, const CropRect &  cropRect = {}  )

static

This filter takes an SkBlendMode and uses it to composite the two filters together.

Parameters

blender	The blender that defines the compositing operation
background	The Dst pixels used in blending, if null the source bitmap is used.
foreground	The Src pixels used in blending, if null the source bitmap is used. @cropRect Optional rectangle to crop input and output.

Definition at line 144 of file SkBlendImageFilter.cpp.

                                                                     {
    return make_blend(std::move(blender), std::move(background), std::move(foreground), cropRect);
}

Blend() [2/2]

sk_sp< SkImageFilter > SkImageFilters::Blend ( SkBlendMode  mode, sk_sp< SkImageFilter >  background, sk_sp< SkImageFilter >  foreground = nullptr, const CropRect &  cropRect = {}  )

static

This filter takes an SkBlendMode and uses it to composite the two filters together.

Parameters

mode	The blend mode that defines the compositing operation
background	The Dst pixels used in blending, if null the source bitmap is used.
foreground	The Src pixels used in blending, if null the source bitmap is used. @cropRect Optional rectangle to crop input and output.

Definition at line 134 of file SkBlendImageFilter.cpp.

                                                                     {
    return make_blend(SkBlender::Mode(mode),
                      std::move(background),
                      std::move(foreground),
                      cropRect);
}

Blur() [1/2]

static sk_sp< SkImageFilter > SkImageFilters::Blur ( SkScalar  sigmaX, SkScalar  sigmaY, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

inlinestatic

Definition at line 126 of file SkImageFilters.h.

                                                                {}) {
        return Blur(sigmaX, sigmaY, SkTileMode::kDecal, std::move(input), cropRect);
    }

Blur() [2/2]

sk_sp< SkImageFilter > SkImageFilters::Blur ( SkScalar  sigmaX, SkScalar  sigmaY, SkTileMode  tileMode, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that blurs its input by the separate X and Y sigmas. The provided tile mode is used when the blur kernel goes outside the input image.

Parameters

sigmaX	The Gaussian sigma value for blurring along the X axis.
sigmaY	The Gaussian sigma value for blurring along the Y axis.
tileMode	The tile mode applied at edges . TODO (michaelludwig) - kMirror is not supported yet
input	The input filter that is blurred, uses source bitmap if this is null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 107 of file SkBlurImageFilter.cpp.

                                  {
    if (!SkIsFinite(sigmaX, sigmaY) || sigmaX < 0.f || sigmaY < 0.f) {
        // Non-finite or negative sigmas are error conditions. We allow 0 sigma for X and/or Y
        // for 1D blurs; onFilterImage() will detect when no visible blurring would occur based on
        // the Context mapping.
        return nullptr;
    }
 
    // Temporarily allow tiling with no crop rect
    if (tileMode != SkTileMode::kDecal && !cropRect) {
        return sk_make_sp<SkBlurImageFilter>(SkSize{sigmaX, sigmaY}, tileMode, std::move(input));
    }
 
    // The 'tileMode' behavior is not well-defined if there is no crop. We only apply it if
    // there is a provided 'cropRect'.
    sk_sp<SkImageFilter> filter = std::move(input);
    if (tileMode != SkTileMode::kDecal && cropRect) {
        // Historically the input image was restricted to the cropRect when tiling was not
        // kDecal, so that the kernel evaluated the tiled edge conditions, while a kDecal crop
        // only affected the output.
        filter = SkImageFilters::Crop(*cropRect, tileMode, std::move(filter));
    }
 
    filter = sk_make_sp<SkBlurImageFilter>(SkSize{sigmaX, sigmaY}, std::move(filter));
    if (cropRect) {
        // But regardless of the tileMode, the output is always decal cropped
        filter = SkImageFilters::Crop(*cropRect, SkTileMode::kDecal, std::move(filter));
    }
    return filter;
}

ColorFilter()

sk_sp< SkImageFilter > SkImageFilters::ColorFilter ( sk_sp< SkColorFilter >  cf, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that applies the color filter to the input filter results.

Parameters

cf	The color filter that transforms the input image.
input	The input filter, or uses the source bitmap if this is null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 72 of file SkColorFilterImageFilter.cpp.

                                                                           {
    if (cf) {
        SkColorFilter* inputCF;
        // This is an optimization, as it collapses the hierarchy by just combining the two
        // colorfilters into a single one, which the new imagefilter will wrap.
        // NOTE: FilterResults are capable of composing non-adjacent CF nodes together. We could
        // remove this optimization at construction time, but may as well do the work just once.
        if (input && input->isColorFilterNode(&inputCF)) {
            cf = cf->makeComposed(sk_sp<SkColorFilter>(inputCF));
            input = sk_ref_sp(input->getInput(0));
        }
    }
 
    sk_sp<SkImageFilter> filter = std::move(input);
    if (cf) {
        filter = sk_sp<SkImageFilter>(
                new SkColorFilterImageFilter(std::move(cf), std::move(filter)));
    }
    if (cropRect) {
        filter = SkImageFilters::Crop(*cropRect, std::move(filter));
    }
    return filter;
}

Compose()

sk_sp< SkImageFilter > SkImageFilters::Compose ( sk_sp< SkImageFilter >  outer, sk_sp< SkImageFilter >  inner  )

static

Create a filter that composes 'inner' with 'outer', such that the results of 'inner' are treated as the source bitmap passed to 'outer', i.e. result = outer(inner(source)).

Parameters

outer	The outer filter that evaluates the results of inner.
inner	The inner filter that produces the input to outer.

Definition at line 66 of file SkComposeImageFilter.cpp.

                                                                         {
    if (!outer) {
        return inner;
    }
    if (!inner) {
        return outer;
    }
    sk_sp<SkImageFilter> inputs[2] = { std::move(outer), std::move(inner) };
    return sk_sp<SkImageFilter>(new SkComposeImageFilter(inputs));
}

Crop() [1/2]

static sk_sp< SkImageFilter > SkImageFilters::Crop ( const SkRect &  rect, sk_sp< SkImageFilter >  input  )

inlinestatic

Definition at line 165 of file SkImageFilters.h.

                                                                                     {
        return Crop(rect, SkTileMode::kDecal, std::move(input));
    }

Crop() [2/2]

sk_sp< SkImageFilter > SkImageFilters::Crop ( const SkRect &  rect, SkTileMode  tileMode, sk_sp< SkImageFilter >  input  )

static

Create a filter that applies a crop to the result of the 'input' filter. Pixels within the crop rectangle are unmodified from what 'input' produced. Pixels outside of crop match the provided SkTileMode (defaulting to kDecal).

NOTE: The optional CropRect argument for many of the factories is equivalent to creating the filter without a CropRect and then wrapping it in ::Crop(rect, kDecal). Explicitly adding Crop filters lets you control their tiling and use different geometry for the input and the output of another filter.

Parameters

rect	The cropping geometry
tileMode	The tilemode applied to pixels outside of 'crop'
input	The input filter that is cropped, uses source image if this is null

Definition at line 99 of file SkCropImageFilter.cpp.

                                                                      {
    if (!SkIsValidRect(rect)) {
        return nullptr;
    }
    return sk_sp<SkImageFilter>(new SkCropImageFilter(rect, tileMode, std::move(input)));
}

Dilate()

sk_sp< SkImageFilter > SkImageFilters::Dilate ( SkScalar  radiusX, SkScalar  radiusY, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that dilates each input pixel's channel values to the max value within the given radii along the x and y axes.

Parameters

radiusX	The distance to dilate along the x axis to either side of each pixel.
radiusY	The distance to dilate along the y axis to either side of each pixel.
input	The image filter that is dilated, using source bitmap if this is null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 227 of file SkMorphologyImageFilter.cpp.

                                                                      {
    return make_morphology(MorphType::kDilate, {radiusX, radiusY}, std::move(input), cropRect);
}

DisplacementMap()

sk_sp< SkImageFilter > SkImageFilters::DisplacementMap ( SkColorChannel  xChannelSelector, SkColorChannel  yChannelSelector, SkScalar  scale, sk_sp< SkImageFilter >  displacement, sk_sp< SkImageFilter >  color, const CropRect &  cropRect = {}  )

static

Create a filter that moves each pixel in its color input based on an (x,y) vector encoded in its displacement input filter. Two color components of the displacement image are mapped into a vector as scale * (color[xChannel], color[yChannel]), where the channel selectors are one of R, G, B, or A.

Parameters

xChannelSelector	RGBA channel that encodes the x displacement per pixel.
yChannelSelector	RGBA channel that encodes the y displacement per pixel.
scale	Scale applied to displacement extracted from image.
displacement	The filter defining the displacement image, or null to use source.
color	The filter providing the color pixels to be displaced. If null, it will use the source.
cropRect	Optional rectangle that crops the color input and output.

Definition at line 144 of file SkDisplacementMapImageFilter.cpp.

                                                                                                 {
    if (!channel_selector_type_is_valid(xChannelSelector) ||
        !channel_selector_type_is_valid(yChannelSelector)) {
        return nullptr;
    }
 
    sk_sp<SkImageFilter> inputs[2] = { std::move(displacement), std::move(color) };
    sk_sp<SkImageFilter> filter(new SkDisplacementMapImageFilter(xChannelSelector, yChannelSelector,
                                                                 scale, inputs));
    if (cropRect) {
        filter = SkImageFilters::Crop(*cropRect, std::move(filter));
    }
    return filter;
}

DistantLitDiffuse()

sk_sp< SkImageFilter > SkImageFilters::DistantLitDiffuse ( const SkPoint3 &  direction, SkColor  lightColor, SkScalar  surfaceScale, SkScalar  kd, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that calculates the diffuse illumination from a distant light source, interpreting the alpha channel of the input as the height profile of the surface (to approximate normal vectors).

Parameters

direction	The direction to the distance light.
lightColor	The color of the diffuse light source.
surfaceScale	Scale factor to transform from alpha values to physical height.
kd	Diffuse reflectance coefficient.
input	The input filter that defines surface normals (as alpha), or uses the source bitmap when null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 314 of file SkLightingImageFilter.cpp.

                                                              {
    return make_lighting(Light::Distant(lightColor, direction),
                         Material::Diffuse(kd, surfaceScale),
                         std::move(input), cropRect);
}

DistantLitSpecular()

sk_sp< SkImageFilter > SkImageFilters::DistantLitSpecular ( const SkPoint3 &  direction, SkColor  lightColor, SkScalar  surfaceScale, SkScalar  ks, SkScalar  shininess, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that calculates the specular illumination from a distant light source, interpreting the alpha channel of the input as the height profile of the surface (to approximate normal vectors).

Parameters

direction	The direction to the distance light.
lightColor	The color of the specular light source.
surfaceScale	Scale factor to transform from alpha values to physical height.
ks	Specular reflectance coefficient.
shininess	The specular exponent determining how shiny the surface is.
input	The input filter that defines surface normals (as alpha), or uses the source bitmap when null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 341 of file SkLightingImageFilter.cpp.

                                                                                  {
    return make_lighting(Light::Distant(lightColor, direction),
                         Material::Specular(ks, shininess, surfaceScale),
                         std::move(input), cropRect);
}

DropShadow()

sk_sp< SkImageFilter > SkImageFilters::DropShadow ( SkScalar  dx, SkScalar  dy, SkScalar  sigmaX, SkScalar  sigmaY, SkColor  color, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that draws a drop shadow under the input content. This filter produces an image that includes the inputs' content.

Parameters

dx	The X offset of the shadow.
dy	The Y offset of the shadow.
sigmaX	The blur radius for the shadow, along the X axis.
sigmaY	The blur radius for the shadow, along the Y axis.
color	The color of the drop shadow.
input	The input filter, or will use the source bitmap if this is null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 97 of file SkDropShadowImageFilter.cpp.

                                                              {
    return make_drop_shadow_graph({dx, dy}, {sigmaX, sigmaY}, color, /*shadowOnly=*/false,
                                  std::move(input), cropRect);
}

DropShadowOnly()

sk_sp< SkImageFilter > SkImageFilters::DropShadowOnly ( SkScalar  dx, SkScalar  dy, SkScalar  sigmaX, SkScalar  sigmaY, SkColor  color, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that renders a drop shadow, in exactly the same manner as DropShadow, except that the resulting image does not include the input content. This allows the shadow and input to be composed by a filter DAG in a more flexible manner.

Parameters

dx	The X offset of the shadow.
dy	The Y offset of the shadow.
sigmaX	The blur radius for the shadow, along the X axis.
sigmaY	The blur radius for the shadow, along the Y axis.
color	The color of the drop shadow.
input	The input filter, or will use the source bitmap if this is null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 104 of file SkDropShadowImageFilter.cpp.

                                                              {
    return make_drop_shadow_graph({dx, dy}, {sigmaX, sigmaY}, color, /*shadowOnly=*/true,
                                  std::move(input), cropRect);
}

Empty()

sk_sp< SkImageFilter > SkImageFilters::Empty ( )

static

Create a filter that always produces transparent black.

Definition at line 110 of file SkCropImageFilter.cpp.

                                           {
    return SkImageFilters::Crop(SkRect::MakeEmpty(), SkTileMode::kDecal, nullptr);
}

Erode()

sk_sp< SkImageFilter > SkImageFilters::Erode ( SkScalar  radiusX, SkScalar  radiusY, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that erodes each input pixel's channel values to the minimum channel value within the given radii along the x and y axes.

Parameters

radiusX	The distance to erode along the x axis to either side of each pixel.
radiusY	The distance to erode along the y axis to either side of each pixel.
input	The image filter that is eroded, using source bitmap if this is null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 233 of file SkMorphologyImageFilter.cpp.

                                                                     {
    return make_morphology(MorphType::kErode, {radiusX, radiusY}, std::move(input), cropRect);
}

Image() [1/2]

sk_sp< SkImageFilter > SkImageFilters::Image ( sk_sp< SkImage >  image, const SkRect &  srcRect, const SkRect &  dstRect, const SkSamplingOptions &  sampling  )

static

Create a filter that draws the 'srcRect' portion of image into 'dstRect' using the given filter quality. Similar to SkCanvas::drawImageRect. The returned image filter evaluates to transparent black if 'image' is null.

Parameters

image	The image that is output by the filter, subset by 'srcRect'.
srcRect	The source pixels sampled into 'dstRect'
dstRect	The local rectangle to draw the image into.
sampling	The sampling to use when drawing the image.

Definition at line 77 of file SkImageImageFilter.cpp.

                                                                              {
    if (srcRect.isEmpty() || dstRect.isEmpty() || !image) {
        // There is no content to draw, so the filter should produce transparent black
        return SkImageFilters::Empty();
    } else {
        SkRect imageBounds = SkRect::Make(image->dimensions());
        if (imageBounds.contains(srcRect)) {
            // No change to srcRect and dstRect needed
            return sk_sp<SkImageFilter>(new SkImageImageFilter(
                    std::move(image), srcRect, dstRect, sampling));
        } else {
            SkMatrix srcToDst = SkMatrix::RectToRect(srcRect, dstRect);
            if (!imageBounds.intersect(srcRect)) {
                // No overlap, so draw empty
                return SkImageFilters::Empty();
            }
 
            // Adjust dstRect to match the updated src (which is stored in imageBounds)
            SkRect mappedBounds = srcToDst.mapRect(imageBounds);
            if (mappedBounds.isEmpty()) {
                return SkImageFilters::Empty();
            }
            return sk_sp<SkImageFilter>(new SkImageImageFilter(
                    std::move(image), imageBounds, mappedBounds, sampling));
        }
    }
}

Image() [2/2]

static sk_sp< SkImageFilter > SkImageFilters::Image ( sk_sp< SkImage >  image, const SkSamplingOptions &  sampling  )

inlinestatic

Create a filter that draws the image using the given sampling. Similar to SkCanvas::drawImage. The returned image filter evaluates to transparent black if 'image' is null.

Parameters

image	The image that is output by the filter.
sampling	The sampling to use when drawing the image.

Definition at line 246 of file SkImageFilters.h.

                                                                                               {
        if (image) {
            SkRect r = SkRect::Make(image->bounds());
            return Image(std::move(image), r, r, sampling);
        } else {
            return nullptr;
        }
    }

Magnifier()

sk_sp< SkImageFilter > SkImageFilters::Magnifier ( const SkRect &  lensBounds, SkScalar  zoomAmount, SkScalar  inset, const SkSamplingOptions &  sampling, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that fills 'lensBounds' with a magnification of the input.

Parameters

lensBounds	The outer bounds of the magnifier effect
zoomAmount	The amount of magnification applied to the input image
inset	The size or width of the fish-eye distortion around the magnified content
sampling	The SkSamplingOptions applied to the input image when magnified
input	The input filter that is magnified; if null the source bitmap is used
cropRect	Optional rectangle that crops the input and output.

Definition at line 82 of file SkMagnifierImageFilter.cpp.

                                                                         {
    if (lensBounds.isEmpty() || !lensBounds.isFinite() ||
        zoomAmount <= 0.f || inset < 0.f ||
        !SkIsFinite(zoomAmount, inset)) {
        return nullptr; // invalid
    }
    // The magnifier automatically restricts its output based on the size of the image it receives
    // as input, so 'cropRect' only applies to its input.
    if (cropRect) {
        input = SkImageFilters::Crop(*cropRect, std::move(input));
    }
 
    if (zoomAmount > 1.f) {
        return sk_sp<SkImageFilter>(new SkMagnifierImageFilter(lensBounds, zoomAmount, inset,
                                                               sampling, std::move(input)));
    } else {
        // Zooming with a value less than 1 is technically a downscaling, which "works" but the
        // non-linear distortion behaves unintuitively. At zoomAmount = 1, this filter is an
        // expensive identity function so treat zoomAmount <= 1 as a no-op.
        return input;
    }
}

MatrixConvolution()

sk_sp< SkImageFilter > SkImageFilters::MatrixConvolution ( const SkISize &  kernelSize, const SkScalar  kernel[], SkScalar  gain, SkScalar  bias, const SkIPoint &  kernelOffset, SkTileMode  tileMode, bool  convolveAlpha, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that applies an NxM image processing kernel to the input image. This can be used to produce effects such as sharpening, blurring, edge detection, etc.

Parameters

kernelSize	The kernel size in pixels, in each dimension (N by M).
kernel	The image processing kernel. Must contain N * M elements, in row order.
gain	A scale factor applied to each pixel after convolution. This can be used to normalize the kernel, if it does not already sum to 1.
bias	A bias factor added to each pixel after convolution.
kernelOffset	An offset applied to each pixel coordinate before convolution. This can be used to center the kernel over the image (e.g., a 3x3 kernel should have an offset of {1, 1}).
tileMode	How accesses outside the image are treated. TODO (michaelludwig) - kMirror is not supported yet
convolveAlpha	If true, all channels are convolved. If false, only the RGB channels are convolved, and alpha is copied from the source image.
input	The input image filter, if null the source bitmap is used instead.
cropRect	Optional rectangle to which the output processing will be limited.

Definition at line 227 of file SkMatrixConvolutionImageFilter.cpp.

                                                                                 {
    if (kernelSize.width() < 1 || kernelSize.height() < 1) {
        return nullptr;
    }
    if (SkSafeMath::Mul(kernelSize.width(), kernelSize.height()) > kMaxKernelSize) {
        return nullptr;
    }
    if (!kernel) {
        return nullptr;
    }
    if ((kernelOffset.fX < 0) || (kernelOffset.fX >= kernelSize.fWidth) ||
        (kernelOffset.fY < 0) || (kernelOffset.fY >= kernelSize.fHeight)) {
        return nullptr;
    }
 
    // The 'tileMode' behavior is not well-defined if there is no crop, so we only apply it if
    // there is a provided 'cropRect'.
    sk_sp<SkImageFilter> filter = std::move(input);
    if (cropRect && tileMode != SkTileMode::kDecal) {
        // Historically the input image was restricted to the cropRect when tiling was not kDecal
        // so that the kernel evaluated the tiled edge conditions, while a kDecal crop only affected
        // the output.
        filter = SkImageFilters::Crop(*cropRect, tileMode, std::move(filter));
    }
    filter = sk_sp<SkImageFilter>(new SkMatrixConvolutionImageFilter(
            kernelSize, kernel, gain, bias, kernelOffset, convolveAlpha, &filter));
    if (cropRect) {
        // But regardless of the tileMode, the output is decal cropped.
        filter = SkImageFilters::Crop(*cropRect, SkTileMode::kDecal, std::move(filter));
    }
    return filter;
}

MatrixTransform()

sk_sp< SkImageFilter > SkImageFilters::MatrixTransform ( const SkMatrix &  matrix, const SkSamplingOptions &  sampling, sk_sp< SkImageFilter >  input  )

static

Create a filter that transforms the input image by 'matrix'. This matrix transforms the local space, which means it effectively happens prior to any transformation coming from the SkCanvas initiating the filtering.

Parameters

matrix	The matrix to apply to the original content.
sampling	How the image will be sampled when it is transformed
input	The image filter to transform, or null to use the source image.

Definition at line 77 of file SkMatrixTransformImageFilter.cpp.

                                                                                 {
    return sk_sp<SkImageFilter>(new SkMatrixTransformImageFilter(transform,
                                                                 sampling,
                                                                 std::move(input)));
}

Merge() [1/2]

sk_sp< SkImageFilter > SkImageFilters::Merge ( sk_sp< SkImageFilter > *const  filters, int  count, const CropRect &  cropRect = {}  )

static

Create a filter that merges the 'count' filters together by drawing their results in order with src-over blending.

Parameters

filters	The input filter array to merge, which must have 'count' elements. Any null filter pointers will use the source bitmap instead.
count	The number of input filters to be merged.
cropRect	Optional rectangle that crops all input filters and the output.

Definition at line 55 of file SkMergeImageFilter.cpp.

                                                                     {
    if (count <= 0 || !filters) {
        return SkImageFilters::Empty();
    }
 
    sk_sp<SkImageFilter> filter{new SkMergeImageFilter(filters, count)};
    if (cropRect) {
        filter = SkImageFilters::Crop(*cropRect, std::move(filter));
    }
    return filter;
}

Merge() [2/2]

static sk_sp< SkImageFilter > SkImageFilters::Merge ( sk_sp< SkImageFilter >  first, sk_sp< SkImageFilter >  second, const CropRect &  cropRect = {}  )

inlinestatic

Create a filter that merges the results of the two filters together with src-over blending.

Parameters

first	The first input filter, or the source bitmap if this is null.
second	The second input filter, or the source bitmap if this null.
cropRect	Optional rectangle that crops the inputs and output.

Definition at line 325 of file SkImageFilters.h.

                                                                 {}) {
        sk_sp<SkImageFilter> array[] = { std::move(first), std::move(second) };
        return Merge(array, 2, cropRect);
    }

Offset()

sk_sp< SkImageFilter > SkImageFilters::Offset ( SkScalar  dx, SkScalar  dy, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that offsets the input filter by the given vector.

Parameters

dx	The x offset in local space that the image is shifted.
dy	The y offset in local space that the image is shifted.
input	The input that will be moved, if null the source bitmap is used instead.
cropRect	Optional rectangle to crop the input and output.

Definition at line 85 of file SkMatrixTransformImageFilter.cpp.

                                                                      {
    // The legacy ::Offset() implementation rounded its offset vector to layer-space pixels, which
    // is roughly equivalent to using nearest-neighbor sampling with the translation matrix.
    sk_sp<SkImageFilter> offset = SkImageFilters::MatrixTransform(
            SkMatrix::Translate(dx, dy),
            SkFilterMode::kNearest,
            std::move(input));
    // The legacy 'cropRect' applies only to the output of the offset filter.
    if (cropRect) {
        offset = SkImageFilters::Crop(*cropRect, std::move(offset));
    }
    return offset;
}

Picture() [1/2]

static sk_sp< SkImageFilter > SkImageFilters::Picture ( sk_sp< SkPicture >  pic )

inlinestatic

Definition at line 352 of file SkImageFilters.h.

                                                              {
        SkRect target = pic ? pic->cullRect() : SkRect::MakeEmpty();
        return Picture(std::move(pic), target);
    }

Picture() [2/2]

sk_sp< SkImageFilter > SkImageFilters::Picture ( sk_sp< SkPicture >  pic, const SkRect &  targetRect  )

static

Create a filter that produces the SkPicture as its output, clipped to both 'targetRect' and the picture's internal cull rect.

If 'pic' is null, the returned image filter produces transparent black.

Parameters

pic	The picture that is drawn for the filter output.
targetRect	The drawing region for the picture.

Definition at line 66 of file SkPictureImageFilter.cpp.

                                                                                           {
    if (pic) {
        SkRect cullRect = pic->cullRect();
        if (cullRect.intersect(targetRect)) {
            return sk_sp<SkImageFilter>(new SkPictureImageFilter(std::move(pic), cullRect));
        }
    }
    return SkImageFilters::Empty();
}

PointLitDiffuse()

sk_sp< SkImageFilter > SkImageFilters::PointLitDiffuse ( const SkPoint3 &  location, SkColor  lightColor, SkScalar  surfaceScale, SkScalar  kd, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that calculates the diffuse illumination from a point light source, using alpha channel of the input as the height profile of the surface (to approximate normal vectors).

Parameters

location	The location of the point light.
lightColor	The color of the diffuse light source.
surfaceScale	Scale factor to transform from alpha values to physical height.
kd	Diffuse reflectance coefficient.
input	The input filter that defines surface normals (as alpha), or uses the source bitmap when null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 322 of file SkLightingImageFilter.cpp.

                                                              {
    return make_lighting(Light::Point(lightColor, location),
                         Material::Diffuse(kd, surfaceScale),
                         std::move(input), cropRect);
}

PointLitSpecular()

sk_sp< SkImageFilter > SkImageFilters::PointLitSpecular ( const SkPoint3 &  location, SkColor  lightColor, SkScalar  surfaceScale, SkScalar  ks, SkScalar  shininess, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that calculates the specular illumination from a point light source, using alpha channel of the input as the height profile of the surface (to approximate normal vectors).

Parameters

location	The location of the point light.
lightColor	The color of the specular light source.
surfaceScale	Scale factor to transform from alpha values to physical height.
ks	Specular reflectance coefficient.
shininess	The specular exponent determining how shiny the surface is.
input	The input filter that defines surface normals (as alpha), or uses the source bitmap when null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 349 of file SkLightingImageFilter.cpp.

                                                                                  {
    return make_lighting(Light::Point(lightColor, location),
                         Material::Specular(ks, shininess, surfaceScale),
                         std::move(input), cropRect);
}

RuntimeShader() [1/4]

sk_sp< SkImageFilter > SkImageFilters::RuntimeShader ( const SkRuntimeShaderBuilder &  builder, SkScalar  maxSampleRadius, std::string_view  childShaderNames[], const sk_sp< SkImageFilter >  inputs[], int  inputCount  )

static

As above, but 'maxSampleRadius' defines the sampling limit on coordinates provided to all child shaders. Like the single-child variant with a sample radius, this can be used to inform Skia that the runtime shader guarantees that all dynamic children (defined in childShaderNames) will be evaluated with coordinates at most 'maxSampleRadius' away from the coordinate provided to the runtime shader itself.

This requires a GPU backend or SkSL to be compiled in.

Definition at line 116 of file SkRuntimeImageFilter.cpp.

                                                                   {
    if (maxSampleRadius < 0.f) {
        return nullptr; // invalid sample radius
    }
 
    auto child_is_shader = [](const SkRuntimeEffect::Child* child) {
        return child && child->type == SkRuntimeEffect::ChildType::kShader;
    };
 
    for (int i = 0; i < inputCount; i++) {
        std::string_view name = childShaderNames[i];
        // All names must be non-empty, and present as a child shader in the effect:
        if (name.empty() || !child_is_shader(builder.effect()->findChild(name))) {
            return nullptr;
        }
 
        // We don't allow duplicates, either:
        for (int j = 0; j < i; j++) {
            if (name == childShaderNames[j]) {
                return nullptr;
            }
        }
    }
 
    return sk_sp<SkImageFilter>(new SkRuntimeImageFilter(builder, maxSampleRadius, childShaderNames,
                                                         inputs, inputCount));
}

RuntimeShader() [2/4]

sk_sp< SkImageFilter > SkImageFilters::RuntimeShader ( const SkRuntimeShaderBuilder &  builder, SkScalar  sampleRadius, std::string_view  childShaderName, sk_sp< SkImageFilter >  input  )

static

As above, but 'sampleRadius' defines the sampling radius of 'childShaderName' relative to the runtime shader produced by 'builder'. If greater than 0, the coordinate passed to childShader.eval() will be up to 'sampleRadius' away (maximum absolute offset in 'x' or 'y') from the coordinate passed into the runtime shader.

This allows Skia to provide sampleable values for the image filter without worrying about boundary conditions.

This requires a GPU backend or SkSL to be compiled in.

Definition at line 99 of file SkRuntimeImageFilter.cpp.

                                                                               {
    // If no childShaderName is provided, check to see if we can implicitly assign it to the only
    // child in the effect.
    if (childShaderName.empty()) {
        auto children = builder.effect()->children();
        if (children.size() != 1) {
            return nullptr;
        }
        childShaderName = children.front().name;
    }
 
    return SkImageFilters::RuntimeShader(builder, sampleRadius, &childShaderName, &input, 1);
}

RuntimeShader() [3/4]

static sk_sp< SkImageFilter > SkImageFilters::RuntimeShader ( const SkRuntimeShaderBuilder &  builder, std::string_view  childShaderName, sk_sp< SkImageFilter >  input  )

inlinestatic

Create a filter that fills the output with the per-pixel evaluation of the SkShader produced by the SkRuntimeShaderBuilder. The shader is defined in the image filter's local coordinate system, so it will automatically be affected by SkCanvas' transform.

This variant assumes that the runtime shader samples 'childShaderName' with the same input coordinate passed to to shader.

This requires a GPU backend or SkSL to be compiled in.

Parameters

builder	The builder used to produce the runtime shader, that will in turn fill the result image
childShaderName	The name of the child shader defined in the builder that will be bound to the input param (or the source image if the input param is null). If empty, the builder can have exactly one child shader, which automatically binds the input param.
input	The image filter that will be provided as input to the runtime shader. If null the implicit source image is used instead

Definition at line 376 of file SkImageFilters.h.

                                                                          {
        return RuntimeShader(builder, /*sampleRadius=*/0.f, childShaderName, std::move(input));
    }

RuntimeShader() [4/4]

static sk_sp< SkImageFilter > SkImageFilters::RuntimeShader ( const SkRuntimeShaderBuilder &  builder, std::string_view  childShaderNames[], const sk_sp< SkImageFilter >  inputs[], int  inputCount  )

inlinestatic

Create a filter that fills the output with the per-pixel evaluation of the SkShader produced by the SkRuntimeShaderBuilder. The shader is defined in the image filter's local coordinate system, so it will automatically be affected by SkCanvas' transform.

This requires a GPU backend or SkSL to be compiled in.

Parameters

builder	The builder used to produce the runtime shader, that will in turn fill the result image
childShaderNames	The names of the child shaders defined in the builder that will be bound to the input params (or the source image if the input param is null). If any name is null, or appears more than once, factory fails and returns nullptr.
inputs	The image filters that will be provided as input to the runtime shader. If any are null, the implicit source image is used instead.
inputCount	How many entries are present in 'childShaderNames' and 'inputs'.

Definition at line 415 of file SkImageFilters.h.

                                                              {
        return RuntimeShader(builder, /*maxSampleRadius=*/0.f, childShaderNames,
                             inputs, inputCount);
    }

Shader() [1/2]

static sk_sp< SkImageFilter > SkImageFilters::Shader ( sk_sp< SkShader >  shader, const CropRect &  cropRect = {}  )

inlinestatic

Create a filter that fills the output with the per-pixel evaluation of the SkShader. The shader is defined in the image filter's local coordinate system, so will automatically be affected by SkCanvas' transform.

Like Image() and Picture(), this is a leaf filter that can be used to introduce inputs to a complex filter graph, but should generally be combined with a filter that as at least one null input to use the implicit source image.

Returns an image filter that evaluates to transparent black if 'shader' is null.

Parameters

shader

The shader that fills the result image

Definition at line 456 of file SkImageFilters.h.

                                                                                          {}) {
        return Shader(std::move(shader), Dither::kNo, cropRect);
    }

Shader() [2/2]

sk_sp< SkImageFilter > SkImageFilters::Shader ( sk_sp< SkShader >  shader, Dither  dither, const CropRect &  cropRect = {}  )

static

Definition at line 70 of file SkShaderImageFilter.cpp.

                                                                      {
    if (!shader) {
        return SkImageFilters::Empty();
    }
 
    sk_sp<SkImageFilter> filter{new SkShaderImageFilter(std::move(shader), dither)};
    if (cropRect) {
        filter = SkImageFilters::Crop(*cropRect, std::move(filter));
    }
    return filter;
}

SpotLitDiffuse()

sk_sp< SkImageFilter > SkImageFilters::SpotLitDiffuse ( const SkPoint3 &  location, const SkPoint3 &  target, SkScalar  falloffExponent, SkScalar  cutoffAngle, SkColor  lightColor, SkScalar  surfaceScale, SkScalar  kd, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that calculates the diffuse illumination from a spot light source, using alpha channel of the input as the height profile of the surface (to approximate normal vectors). The spot light is restricted to be within 'cutoffAngle' of the vector between the location and target.

Parameters

location	The location of the spot light.
target	The location that the spot light is point towards
falloffExponent	Exponential falloff parameter for illumination outside of cutoffAngle
cutoffAngle	Maximum angle from lighting direction that receives full light
lightColor	The color of the diffuse light source.
surfaceScale	Scale factor to transform from alpha values to physical height.
kd	Diffuse reflectance coefficient.
input	The input filter that defines surface normals (as alpha), or uses the source bitmap when null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 330 of file SkLightingImageFilter.cpp.

                                                              {
    SkPoint3 dir = target - location;
    float cosCutoffAngle = SkScalarCos(SkDegreesToRadians(cutoffAngle));
    return make_lighting(Light::Spot(lightColor, location, dir, falloffExponent, cosCutoffAngle),
                         Material::Diffuse(kd, surfaceScale),
                         std::move(input), cropRect);
}

SpotLitSpecular()

sk_sp< SkImageFilter > SkImageFilters::SpotLitSpecular ( const SkPoint3 &  location, const SkPoint3 &  target, SkScalar  falloffExponent, SkScalar  cutoffAngle, SkColor  lightColor, SkScalar  surfaceScale, SkScalar  ks, SkScalar  shininess, sk_sp< SkImageFilter >  input, const CropRect &  cropRect = {}  )

static

Create a filter that calculates the specular illumination from a spot light source, using alpha channel of the input as the height profile of the surface (to approximate normal vectors). The spot light is restricted to be within 'cutoffAngle' of the vector between the location and target.

Parameters

location	The location of the spot light.
target	The location that the spot light is point towards
falloffExponent	Exponential falloff parameter for illumination outside of cutoffAngle
cutoffAngle	Maximum angle from lighting direction that receives full light
lightColor	The color of the specular light source.
surfaceScale	Scale factor to transform from alpha values to physical height.
ks	Specular reflectance coefficient.
shininess	The specular exponent determining how shiny the surface is.
input	The input filter that defines surface normals (as alpha), or uses the source bitmap when null.
cropRect	Optional rectangle that crops the input and output.

Definition at line 357 of file SkLightingImageFilter.cpp.

                                                                                  {
    SkPoint3 dir = target - location;
    float cosCutoffAngle = SkScalarCos(SkDegreesToRadians(cutoffAngle));
    return make_lighting(Light::Spot(lightColor, location, dir, falloffExponent, cosCutoffAngle),
                         Material::Specular(ks, shininess, surfaceScale),
                         std::move(input), cropRect);
}

Tile()

sk_sp< SkImageFilter > SkImageFilters::Tile ( const SkRect &  src, const SkRect &  dst, sk_sp< SkImageFilter >  input  )

static

Create a tile image filter.

Parameters

src	Defines the pixels to tile
dst	Defines the pixel region that the tiles will be drawn to
input	The input that will be tiled, if null the source bitmap is used instead.

Definition at line 114 of file SkCropImageFilter.cpp.

                                                                      {
    // The Tile filter is simply a crop to 'src' with a kRepeat tile mode wrapped in a crop to 'dst'
    // with a kDecal tile mode.
    sk_sp<SkImageFilter> filter = SkImageFilters::Crop(src, SkTileMode::kRepeat, std::move(input));
    filter = SkImageFilters::Crop(dst, SkTileMode::kDecal, std::move(filter));
    return filter;
}

---

The documentation for this class was generated from the following files:

• third_party/skia/include/effects/SkImageFilters.h
• third_party/skia/src/effects/imagefilters/SkBlendImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkBlurImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkColorFilterImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkComposeImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkCropImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkDisplacementMapImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkDropShadowImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkImageImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkLightingImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkMagnifierImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkMatrixConvolutionImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkMatrixTransformImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkMergeImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkMorphologyImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkPictureImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkRuntimeImageFilter.cpp
• third_party/skia/src/effects/imagefilters/SkShaderImageFilter.cpp