localmatrixshader.cpp File Reference

#include "gm/gm.h"
#include "include/core/SkBitmap.h"
#include "include/core/SkBlendMode.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkImage.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkRect.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "include/core/SkShader.h"
#include "include/core/SkSurface.h"
#include "include/core/SkTypes.h"
#include "include/effects/SkGradientShader.h"
#include "tools/DecodeUtils.h"
#include "tools/GpuToolUtils.h"
#include "tools/Resources.h"
#include "tools/ToolUtils.h"
#include "tools/timer/TimeUtils.h"

Go to the source code of this file.

Classes
class	skiagm::LocalMatrixOrder

Namespaces
namespace	skiagm

Functions
static sk_sp< SkImage >	make_image (SkCanvas *rootCanvas)
	DEF_SIMPLE_GM (localmatrixshader_nested, canvas, 450, 1200)
	DEF_SIMPLE_GM (localmatrixshader_persp, canvas, 542, 266)

Function Documentation

DEF_SIMPLE_GM() [1/2]

DEF_SIMPLE_GM	(	localmatrixshader_nested	,
		canvas	,
		450	,
		1200
	)

Definition at line 50 of file localmatrixshader.cpp.

                                                           {
    auto image = make_image(canvas);
    if (!image) {
        return;
    }
 
    using FactoryT = sk_sp<SkShader> (*)(const sk_sp<SkImage>&,
                                         const SkMatrix& inner,
                                         const SkMatrix& outer);
    static const FactoryT gFactories[] = {
        // SkLocalMatrixShader(SkImageShader(inner), outer)
        [](const sk_sp<SkImage>& img, const SkMatrix& inner, const SkMatrix& outer) {
            return img->makeShader(SkSamplingOptions(), inner)->makeWithLocalMatrix(outer);
        },
 
        // SkLocalMatrixShader(SkLocalMatrixShader(SkImageShader(I), inner), outer)
        [](const sk_sp<SkImage>& img, const SkMatrix& inner, const SkMatrix& outer) {
            return img->makeShader(SkSamplingOptions())->makeWithLocalMatrix(inner)->makeWithLocalMatrix(outer);
        },
 
        // SkLocalMatrixShader(SkComposeShader(SkImageShader(inner)), outer)
        [](const sk_sp<SkImage>& img, const SkMatrix& inner, const SkMatrix& outer) {
            return SkShaders::Blend(SkBlendMode::kSrcOver,
                                    SkShaders::Color(SK_ColorTRANSPARENT),
                                    img->makeShader(SkSamplingOptions(), inner))
                   ->makeWithLocalMatrix(outer);
        },
 
        // SkLocalMatrixShader(SkComposeShader(SkLocalMatrixShader(SkImageShader(I), inner)), outer)
        [](const sk_sp<SkImage>& img, const SkMatrix& inner, const SkMatrix& outer) {
            return SkShaders::Blend(SkBlendMode::kSrcOver,
                                    SkShaders::Color(SK_ColorTRANSPARENT),
                                    img->makeShader(SkSamplingOptions())->makeWithLocalMatrix(inner))
                   ->makeWithLocalMatrix(outer);
        },
    };
 
    static const auto outer = SkMatrix::Scale(2, 2),
                      inner = SkMatrix::Translate(20, 20);
 
    SkPaint border;
    border.setAntiAlias(true);
    border.setStyle(SkPaint::kStroke_Style);
 
    auto rect = SkRect::Make(image->bounds());
    SkAssertResult(SkMatrix::Concat(outer, inner).mapRect(&rect));
 
    const auto drawColumn = [&]() {
        SkAutoCanvasRestore acr(canvas, true);
        for (const auto& f : gFactories) {
            SkPaint p;
            p.setShader(f(image, inner, outer));
 
            canvas->drawRect(rect, p);
            canvas->drawRect(rect, border);
 
            canvas->translate(0, rect.height() * 1.5f);
        }
    };
 
    drawColumn();
 
    {
        SkAutoCanvasRestore acr(canvas, true);
        canvas->translate(0, rect.height() * std::size(gFactories) * 1.5f);
        drawColumn();
    }
 
    canvas->translate(rect.width() * 1.5f, 0);
    canvas->scale(2, 2);
    drawColumn();
}

DEF_SIMPLE_GM() [2/2]

DEF_SIMPLE_GM	(	localmatrixshader_persp	,
		canvas	,
		542	,
		266
	)

Definition at line 123 of file localmatrixshader.cpp.

                                                         {
    auto image = ToolUtils::GetResourceAsImage("images/yellow_rose.png");
 
    SkBitmap downsized;
    downsized.allocPixels(image->imageInfo().makeWH(128, 128));
    image->scalePixels(downsized.pixmap(), SkSamplingOptions(SkFilterMode::kLinear));
    image = downsized.asImage();
    SkRect imgRect = SkRect::MakeIWH(image->width(), image->height());
 
    // scale matrix
    SkMatrix scale = SkMatrix::Scale(1.f / 5.f, 1.f / 5.f);
 
    // perspective matrix
    SkPoint src[4];
    imgRect.toQuad(src);
    SkPoint dst[4] = {{0, 10.f},
                      {image->width() + 28.f, -100.f},
                      {image->width() - 28.f, image->height() + 100.f},
                      {0.f, image->height() - 10.f}};
    SkMatrix persp;
    SkAssertResult(persp.setPolyToPoly(src, dst, 4));
 
    // combined persp * scale
    SkMatrix perspScale = SkMatrix::Concat(persp, scale);
 
    auto draw = [&](sk_sp<SkShader> shader, bool applyPerspToCTM) {
        canvas->save();
        canvas->clipRect(imgRect);
        if (applyPerspToCTM) {
            canvas->concat(persp);
        }
        SkPaint imgShaderPaint;
        imgShaderPaint.setShader(std::move(shader));
        canvas->drawPaint(imgShaderPaint);
        canvas->restore();
 
        canvas->translate(10.f + image->width(), 0.f); // advance
    };
 
    // SkImageShader
    canvas->save();
    // 4 variants that all attempt to apply sample at persp * scale w/ an image shader
    // 1. scale provided to SkImage::makeShader(...) but drawn with persp
    auto s1 = image->makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat,
                                SkSamplingOptions(), &scale);
    draw(s1, true);
 
    // 2. scale provided to SkImage::makeShader, then wrapped in persp makeWithLocalMatrix
    // These post-concat, so it ends up as persp * scale.
    auto s2 = image->makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat,
                                SkSamplingOptions(), &scale)
                   ->makeWithLocalMatrix(persp);
    draw(s2, false);
 
    // 3. Providing pre-computed persp*scale to SkImage::makeShader()
    auto s3 = image->makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat,
                                SkSamplingOptions(), &perspScale);
    draw(s3, false);
 
    // 4. Providing pre-computed persp*scale to makeWithLocalMatrix
    auto s4 = image->makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat, SkSamplingOptions())
                   ->makeWithLocalMatrix(perspScale);
    draw(s4, false);
    canvas->restore();
 
    canvas->translate(0.f, 10.f + image->height()); // advance to next row
 
    // SkGradientShader
    const SkColor kGradColors[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
    canvas->save();
    // 1. scale provided to Make, drawn with persp
    auto g1 = SkGradientShader::MakeRadial({imgRect.centerX(), imgRect.centerY()},
                                           imgRect.width() / 2.f, kGradColors, nullptr, 2,
                                           SkTileMode::kRepeat, 0, &scale);
    draw(g1, true);
 
    // 2. scale provided to Make, then wrapped with makeWithLocalMatrix (post-concat as before).
    auto g2 = SkGradientShader::MakeRadial({imgRect.centerX(), imgRect.centerY()},
                                           imgRect.width() / 2.f, kGradColors, nullptr, 2,
                                           SkTileMode::kRepeat, 0, &scale)
                              ->makeWithLocalMatrix(persp);
    draw(g2, false);
 
    // 3. Provide per-computed persp*scale to Make
    auto g3 = SkGradientShader::MakeRadial({imgRect.centerX(), imgRect.centerY()},
                                           imgRect.width() / 2.f, kGradColors, nullptr, 2,
                                           SkTileMode::kRepeat, 0, &perspScale);
    draw(g3, false);
 
    // 4.  Providing pre-computed persp*scale to makeWithLocalMatrix
    auto g4 = SkGradientShader::MakeRadial({imgRect.centerX(), imgRect.centerY()},
                                           imgRect.width() / 2.f, kGradColors, nullptr, 2,
                                           SkTileMode::kRepeat)
                              ->makeWithLocalMatrix(perspScale);
    draw(g4, false);
    canvas->restore();
}

make_image()

static sk_sp< SkImage > make_image ( SkCanvas *  rootCanvas )

static

Definition at line 30 of file localmatrixshader.cpp.

                                                       {
    static constexpr SkScalar kSize = 50;
    SkImageInfo info = SkImageInfo::MakeN32Premul(kSize, kSize);
    auto surface(SkSurfaces::Raster(info));
 
    SkPaint p;
    p.setAntiAlias(true);
    p.setColor(SK_ColorGREEN);
 
    surface->getCanvas()->drawCircle(kSize / 2, kSize / 2, kSize / 2, p);
 
    p.setStyle(SkPaint::kStroke_Style);
    p.setColor(SK_ColorRED);
    surface->getCanvas()->drawLine(kSize * .25f, kSize * .50f, kSize * .75f, kSize * .50f, p);
    surface->getCanvas()->drawLine(kSize * .50f, kSize * .25f, kSize * .50f, kSize * .75f, p);
 
    sk_sp<SkImage> img = surface->makeImageSnapshot();
    return ToolUtils::MakeTextureImage(rootCanvas, std::move(img));
}