flutter::RasterCacheUtil Struct Reference

#include <raster_cache_util.h>

Static Public Member Functions
static bool	CanRasterizeRect (const SkRect &cull_rect)
static SkRect	GetDeviceBounds (const SkRect &rect, const SkMatrix &ctm)
static SkRect	GetRoundedOutDeviceBounds (const SkRect &rect, const SkMatrix &ctm)
static SkMatrix	GetIntegralTransCTM (const SkMatrix &ctm)
	Snap the translation components of the matrix to integers. More...
static bool	ComputeIntegralTransCTM (const SkMatrix &in, SkMatrix *out)
	Snap the translation components of the |in| matrix to integers and store the snapped matrix in |out|. More...
static SkM44	GetIntegralTransCTM (const SkM44 &ctm)
	Snap the translation components of the matrix to integers. More...
static bool	ComputeIntegralTransCTM (const SkM44 &in, SkM44 *out)
	Snap the translation components of the |in| matrix to integers and store the snapped matrix in |out|. More...

Static Public Attributes
static constexpr int	kDefaultPictureAndDisplayListCacheLimitPerFrame = 3
static constexpr int	kMinimumRendersBeforeCachingFilterLayer = 3

Detailed Description

Definition at line 15 of file raster_cache_util.h.

Member Function Documentation

CanRasterizeRect()

static bool flutter::RasterCacheUtil::CanRasterizeRect ( const SkRect &  cull_rect )

inlinestatic

Definition at line 38 of file raster_cache_util.h.

                                                        {
    if (cull_rect.isEmpty()) {
      // No point in ever rasterizing an empty display list.
      return false;
    }
 
    if (!cull_rect.isFinite()) {
      // Cannot attempt to rasterize into an infinitely large surface.
      FML_LOG(INFO) << "Attempted to raster cache non-finite display list";
      return false;
    }
 
    return true;
  }

ComputeIntegralTransCTM() [1/2]

bool flutter::RasterCacheUtil::ComputeIntegralTransCTM ( const SkM44 &  in, SkM44 *  out  )

static

Snap the translation components of the |in| matrix to integers and store the snapped matrix in |out|.

The snapping will only happen if the matrix only has scale and translation transformations. This is used, along with GetRoundedOutDeviceBounds, to ensure that the textures drawn by the raster cache are exactly aligned to physical pixels. Any layers that participate in raster caching must align themselves to physical pixels even when not cached to prevent a change in apparent location if caching is later applied.

The |out| matrix will not be modified if this method returns false.

Parameters

in	the current transformation matrix.
out	the storage for the snapped matrix.

Returns

true if the integral modification was needed, false otherwise.

Definition at line 33 of file raster_cache_util.cc.

                                                                         {
  // Avoid integral snapping if the matrix has complex transformation to avoid
  // the artifact observed in https://github.com/flutter/flutter/issues/41654.
  if (in.rc(0, 1) != 0 || in.rc(0, 2) != 0) {
    // X multiplied by either Y or Z
    return false;
  }
  if (in.rc(1, 0) != 0 || in.rc(1, 2) != 0) {
    // Y multiplied by either X or Z
    return false;
  }
  if (in.rc(3, 0) != 0 || in.rc(3, 1) != 0 || in.rc(3, 2) != 0 ||
      in.rc(3, 3) != 1) {
    // W not identity row, therefore perspective is applied
    return false;
  }
  // We do not need to worry about the Z row unless the W row
  // has perspective entries, which we've just eliminated...
 
  SkScalar in_tx = in.rc(0, 3);
  SkScalar in_ty = in.rc(1, 3);
  SkScalar out_tx = SkScalarRoundToScalar(in_tx);
  SkScalar out_ty = SkScalarRoundToScalar(in_ty);
  if (out_tx != in_tx || out_ty != in_ty) {
    // As a side effect of those tests we also know that neither translation
    // component was a NaN
    *out = in;
    out->setRC(0, 3, out_tx);
    out->setRC(1, 3, out_ty);
    // No need to worry about Z translation because it has no effect
    // without perspective entries...
    return true;
  }
 
  return false;
}

ComputeIntegralTransCTM() [2/2]

bool flutter::RasterCacheUtil::ComputeIntegralTransCTM ( const SkMatrix &  in, SkMatrix *  out  )

static

Snap the translation components of the |in| matrix to integers and store the snapped matrix in |out|.

The snapping will only happen if the matrix only has scale and translation transformations. This is used, along with GetRoundedOutDeviceBounds, to ensure that the textures drawn by the raster cache are exactly aligned to physical pixels. Any layers that participate in raster caching must align themselves to physical pixels even when not cached to prevent a change in apparent location if caching is later applied.

The |out| matrix will not be modified if this method returns false.

Parameters

in	the current transformation matrix.
out	the storage for the snapped matrix.

Returns

true if the integral modification was needed, false otherwise.

Definition at line 9 of file raster_cache_util.cc.

                                                             {
  // Avoid integral snapping if the matrix has complex transformation to avoid
  // the artifact observed in https://github.com/flutter/flutter/issues/41654.
  if (!in.isScaleTranslate()) {
    return false;
  }
 
  SkScalar in_tx = in.getTranslateX();
  SkScalar in_ty = in.getTranslateY();
  SkScalar out_tx = SkScalarRoundToScalar(in_tx);
  SkScalar out_ty = SkScalarRoundToScalar(in_ty);
  if (out_tx != in_tx || out_ty != in_ty) {
    // As a side effect of those tests we also know that neither translation
    // component was a NaN
    *out = in;
    (*out)[SkMatrix::kMTransX] = out_tx;
    (*out)[SkMatrix::kMTransY] = out_ty;
    return true;
  }
 
  return false;
}

GetDeviceBounds()

static SkRect flutter::RasterCacheUtil::GetDeviceBounds ( const SkRect &  rect, const SkMatrix &  ctm  )

inlinestatic

Definition at line 53 of file raster_cache_util.h.

                                                                         {
    SkRect device_rect;
    ctm.mapRect(&device_rect, rect);
    return device_rect;
  }

GetIntegralTransCTM() [1/2]

static SkM44 flutter::RasterCacheUtil::GetIntegralTransCTM ( const SkM44 &  ctm )

inlinestatic

Snap the translation components of the matrix to integers.

The snapping will only happen if the matrix only has scale and translation transformations. This is used, along with GetRoundedOutDeviceBounds, to ensure that the textures drawn by the raster cache are exactly aligned to physical pixels. Any layers that participate in raster caching must align themselves to physical pixels even when not cached to prevent a change in apparent location if caching is later applied.

Parameters

ctm	the current transformation matrix.

Returns

SkM44 the snapped transformation matrix.

Definition at line 117 of file raster_cache_util.h.

                                                     {
    SkM44 integral;
    return ComputeIntegralTransCTM(ctm, &integral) ? integral : ctm;
  }

GetIntegralTransCTM() [2/2]

static SkMatrix flutter::RasterCacheUtil::GetIntegralTransCTM ( const SkMatrix &  ctm )

inlinestatic

Snap the translation components of the matrix to integers.

The snapping will only happen if the matrix only has scale and translation transformations. This is used, along with GetRoundedOutDeviceBounds, to ensure that the textures drawn by the raster cache are exactly aligned to physical pixels. Any layers that participate in raster caching must align themselves to physical pixels even when not cached to prevent a change in apparent location if caching is later applied.

Parameters

ctm	the current transformation matrix.

Returns

SkMatrix the snapped transformation matrix.

Definition at line 80 of file raster_cache_util.h.

                                                           {
    SkMatrix integral;
    return ComputeIntegralTransCTM(ctm, &integral) ? integral : ctm;
  }

GetRoundedOutDeviceBounds()

static SkRect flutter::RasterCacheUtil::GetRoundedOutDeviceBounds ( const SkRect &  rect, const SkMatrix &  ctm  )

inlinestatic

Definition at line 59 of file raster_cache_util.h.

                                                               {
    SkRect device_rect;
    ctm.mapRect(&device_rect, rect);
    device_rect.roundOut(&device_rect);
    return device_rect;
  }

Member Data Documentation

kDefaultPictureAndDisplayListCacheLimitPerFrame

constexpr int flutter::RasterCacheUtil::kDefaultPictureAndDisplayListCacheLimitPerFrame = 3

staticconstexpr

Definition at line 20 of file raster_cache_util.h.

kMinimumRendersBeforeCachingFilterLayer

constexpr int flutter::RasterCacheUtil::kMinimumRendersBeforeCachingFilterLayer = 3

staticconstexpr

Definition at line 36 of file raster_cache_util.h.

---

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

• flow/raster_cache_util.h
• flow/raster_cache_util.cc