// This does a lot of computation to resample only the portion of the bitmap
// that will only be drawn. This is critical for performance since when we are
// scrolling, for example, we are only drawing a small strip of the image.
// Resampling the whole image every time is very slow, so this speeds up things
// dramatically.
//
// Note: this code is only used when the canvas transformation is limited to
// scaling or translation.
void NativeImageSkia::drawResampledBitmap(GraphicsContext* context, SkPaint& paint, const SkRect& srcRect, const SkRect& destRect) const
{
TRACE_EVENT0("skia", "drawResampledBitmap");
// We want to scale |destRect| with transformation in the canvas to obtain
// the final scale. The final scale is a combination of scale transform
// in canvas and explicit scaling (srcRect and destRect).
SkRect screenRect;
context->getTotalMatrix().mapRect(&screenRect, destRect);
float realScaleX = screenRect.width() / srcRect.width();
float realScaleY = screenRect.height() / srcRect.height();
// This part of code limits scaling only to visible portion in the
SkRect destRectVisibleSubset;
if (!context->canvas()->getClipBounds(&destRectVisibleSubset))
return;
// ClipRectToCanvas often overshoots, resulting in a larger region than our
// original destRect. Intersecting gets us back inside.
if (!destRectVisibleSubset.intersect(destRect))
return; // Nothing visible in destRect.
// Find the corresponding rect in the source image.
SkMatrix destToSrcTransform;
SkRect srcRectVisibleSubset;
destToSrcTransform.setRectToRect(destRect, srcRect, SkMatrix::kFill_ScaleToFit);
destToSrcTransform.mapRect(&srcRectVisibleSubset, destRectVisibleSubset);
SkRect scaledSrcRect;
SkBitmap scaledImageFragment = extractScaledImageFragment(srcRectVisibleSubset, realScaleX, realScaleY, &scaledSrcRect);
context->drawBitmapRect(scaledImageFragment, &scaledSrcRect, destRectVisibleSubset, &paint);
}
// This does a lot of computation to resample only the portion of the bitmap
// that will only be drawn. This is critical for performance since when we are
// scrolling, for example, we are only drawing a small strip of the image.
// Resampling the whole image every time is very slow, so this speeds up things
// dramatically.
//
// Note: this code is only used when the canvas transformation is limited to
// scaling or translation.
static void drawResampledBitmap(SkCanvas& canvas, SkPaint& paint, const NativeImageSkia& bitmap, const SkRect& srcRect, const SkRect& destRect)
{
#if PLATFORM(CHROMIUM)
TRACE_EVENT0("skia", "drawResampledBitmap");
#endif
// We want to scale |destRect| with transformation in the canvas to obtain
// the final scale. The final scale is a combination of scale transform
// in canvas and explicit scaling (srcRect and destRect).
SkRect screenRect;
canvas.getTotalMatrix().mapRect(&screenRect, destRect);
float realScaleX = screenRect.width() / srcRect.width();
float realScaleY = screenRect.height() / srcRect.height();
// This part of code limits scaling only to visible portion in the
SkRect destRectVisibleSubset;
ClipRectToCanvas(canvas, destRect, &destRectVisibleSubset);
// ClipRectToCanvas often overshoots, resulting in a larger region than our
// original destRect. Intersecting gets us back inside.
if (!destRectVisibleSubset.intersect(destRect))
return; // Nothing visible in destRect.
// Find the corresponding rect in the source image.
SkMatrix destToSrcTransform;
SkRect srcRectVisibleSubset;
destToSrcTransform.setRectToRect(destRect, srcRect, SkMatrix::kFill_ScaleToFit);
destToSrcTransform.mapRect(&srcRectVisibleSubset, destRectVisibleSubset);
SkRect scaledSrcRect;
SkIRect enclosingScaledSrcRect;
SkBitmap scaledImageFragment = extractScaledImageFragment(bitmap, srcRectVisibleSubset, realScaleX, realScaleY, &scaledSrcRect, &enclosingScaledSrcRect);
// Expand the destination rectangle because the source rectangle was
// expanded to fit to integer boundaries.
SkMatrix scaledSrcToDestTransform;
scaledSrcToDestTransform.setRectToRect(scaledSrcRect, destRectVisibleSubset, SkMatrix::kFill_ScaleToFit);
SkRect enclosingDestRect;
enclosingDestRect.set(enclosingScaledSrcRect);
scaledSrcToDestTransform.mapRect(&enclosingDestRect);
// The reason we do clipping is because Skia doesn't support SkRect as
// source rect. See http://crbug.com/145540.
// When Skia supports then use this as the source rect to replace 0.
//
// scaledSrcRect.offset(-enclosingScaledSrcRect.x(), -enclosingScaledSrcRect.y());
canvas.save();
canvas.clipRect(destRectVisibleSubset);
// Because the image fragment is generated with an approxmiated scaling
// factor. This draw will perform a close to 1 scaling.
//
// NOTE: For future optimization. If the difference in scale is so small
// that Skia doesn't produce a difference then we can just blit it directly
// to enhance performance.
canvas.drawBitmapRect(scaledImageFragment, 0, enclosingDestRect, &paint);
canvas.restore();
}
void Image::drawPattern(GraphicsContext* context,
const FloatRect& floatSrcRect,
const AffineTransform& patternTransform,
const FloatPoint& phase,
ColorSpace styleColorSpace,
CompositeOperator compositeOp,
const FloatRect& destRect)
{
#if PLATFORM(CHROMIUM)
TRACE_EVENT0("skia", "Image::drawPattern");
#endif
FloatRect normSrcRect = normalizeRect(floatSrcRect);
if (destRect.isEmpty() || normSrcRect.isEmpty())
return; // nothing to draw
NativeImageSkia* bitmap = nativeImageForCurrentFrame();
if (!bitmap)
return;
SkMatrix ctm = context->platformContext()->canvas()->getTotalMatrix();
SkMatrix totalMatrix;
totalMatrix.setConcat(ctm, patternTransform);
// Figure out what size the bitmap will be in the destination. The
// destination rect is the bounds of the pattern, we need to use the
// matrix to see how big it will be.
SkRect destRectTarget;
totalMatrix.mapRect(&destRectTarget, normSrcRect);
float destBitmapWidth = SkScalarToFloat(destRectTarget.width());
float destBitmapHeight = SkScalarToFloat(destRectTarget.height());
// Compute the resampling mode.
ResamplingMode resampling;
if (context->platformContext()->isAccelerated() || context->platformContext()->printing())
resampling = RESAMPLE_LINEAR;
else
resampling = computeResamplingMode(totalMatrix, *bitmap, normSrcRect.width(), normSrcRect.height(), destBitmapWidth, destBitmapHeight);
resampling = limitResamplingMode(context->platformContext(), resampling);
// Load the transform WebKit requested.
SkMatrix matrix(patternTransform);
SkShader* shader;
if (resampling == RESAMPLE_AWESOME) {
// Do nice resampling.
float scaleX = destBitmapWidth / normSrcRect.width();
float scaleY = destBitmapHeight / normSrcRect.height();
SkRect scaledSrcRect;
SkIRect enclosingScaledSrcRect;
// The image fragment generated here is not exactly what is
// requested. The scale factor used is approximated and image
// fragment is slightly larger to align to integer
// boundaries.
SkBitmap resampled = extractScaledImageFragment(*bitmap, normSrcRect, scaleX, scaleY, &scaledSrcRect, &enclosingScaledSrcRect);
shader = SkShader::CreateBitmapShader(resampled, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);
// Since we just resized the bitmap, we need to remove the scale
// applied to the pixels in the bitmap shader. This means we need
// CTM * patternTransform to have identity scale. Since we
// can't modify CTM (or the rectangle will be drawn in the wrong
// place), we must set patternTransform's scale to the inverse of
// CTM scale.
matrix.setScaleX(ctm.getScaleX() ? 1 / ctm.getScaleX() : 1);
matrix.setScaleY(ctm.getScaleY() ? 1 / ctm.getScaleY() : 1);
} else {
// No need to do nice resampling.
SkBitmap srcSubset;
bitmap->bitmap().extractSubset(&srcSubset, enclosingIntRect(normSrcRect));
shader = SkShader::CreateBitmapShader(srcSubset, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);
}
// We also need to translate it such that the origin of the pattern is the
// origin of the destination rect, which is what WebKit expects. Skia uses
// the coordinate system origin as the base for the patter. If WebKit wants
// a shifted image, it will shift it from there using the patternTransform.
float adjustedX = phase.x() + normSrcRect.x() *
narrowPrecisionToFloat(patternTransform.a());
float adjustedY = phase.y() + normSrcRect.y() *
narrowPrecisionToFloat(patternTransform.d());
matrix.postTranslate(SkFloatToScalar(adjustedX),
SkFloatToScalar(adjustedY));
shader->setLocalMatrix(matrix);
SkPaint paint;
paint.setShader(shader)->unref();
paint.setXfermodeMode(WebCoreCompositeToSkiaComposite(compositeOp));
paint.setFilterBitmap(resampling == RESAMPLE_LINEAR);
context->platformContext()->paintSkPaint(destRect, paint);
}
void NativeImageSkia::drawPattern(
GraphicsContext* context,
const FloatRect& floatSrcRect,
const FloatSize& scale,
const FloatPoint& phase,
CompositeOperator compositeOp,
const FloatRect& destRect,
WebBlendMode blendMode,
const IntSize& repeatSpacing) const
{
FloatRect normSrcRect = floatSrcRect;
normSrcRect.intersect(FloatRect(0, 0, bitmap().width(), bitmap().height()));
if (destRect.isEmpty() || normSrcRect.isEmpty())
return; // nothing to draw
SkMatrix totalMatrix = context->getTotalMatrix();
AffineTransform ctm = context->getCTM();
SkScalar ctmScaleX = ctm.xScale();
SkScalar ctmScaleY = ctm.yScale();
totalMatrix.preScale(scale.width(), scale.height());
// Figure out what size the bitmap will be in the destination. The
// destination rect is the bounds of the pattern, we need to use the
// matrix to see how big it will be.
SkRect destRectTarget;
totalMatrix.mapRect(&destRectTarget, normSrcRect);
float destBitmapWidth = SkScalarToFloat(destRectTarget.width());
float destBitmapHeight = SkScalarToFloat(destRectTarget.height());
bool isLazyDecoded = DeferredImageDecoder::isLazyDecoded(bitmap());
// Compute the resampling mode.
InterpolationQuality resampling;
if (context->isAccelerated())
resampling = InterpolationLow;
else if (isLazyDecoded)
resampling = InterpolationHigh;
else
resampling = computeInterpolationQuality(totalMatrix, normSrcRect.width(), normSrcRect.height(), destBitmapWidth, destBitmapHeight, isDataComplete());
resampling = limitInterpolationQuality(context, resampling);
SkMatrix localMatrix;
// We also need to translate it such that the origin of the pattern is the
// origin of the destination rect, which is what WebKit expects. Skia uses
// the coordinate system origin as the base for the pattern. If WebKit wants
// a shifted image, it will shift it from there using the localMatrix.
const float adjustedX = phase.x() + normSrcRect.x() * scale.width();
const float adjustedY = phase.y() + normSrcRect.y() * scale.height();
localMatrix.setTranslate(SkFloatToScalar(adjustedX), SkFloatToScalar(adjustedY));
RefPtr<SkShader> shader;
SkFilterQuality filterLevel = static_cast<SkFilterQuality>(resampling);
// Bicubic filter is only applied to defer-decoded images, see
// NativeImageSkia::draw for details.
if (resampling == InterpolationHigh && !isLazyDecoded) {
// Do nice resampling.
filterLevel = kNone_SkFilterQuality;
float scaleX = destBitmapWidth / normSrcRect.width();
float scaleY = destBitmapHeight / normSrcRect.height();
SkRect scaledSrcRect;
// Since we are resizing the bitmap, we need to remove the scale
// applied to the pixels in the bitmap shader. This means we need
// CTM * localMatrix to have identity scale. Since we
// can't modify CTM (or the rectangle will be drawn in the wrong
// place), we must set localMatrix's scale to the inverse of
// CTM scale.
localMatrix.preScale(ctmScaleX ? 1 / ctmScaleX : 1, ctmScaleY ? 1 / ctmScaleY : 1);
// The image fragment generated here is not exactly what is
// requested. The scale factor used is approximated and image
// fragment is slightly larger to align to integer
// boundaries.
SkBitmap resampled = extractScaledImageFragment(normSrcRect, scaleX, scaleY, &scaledSrcRect);
if (repeatSpacing.isZero()) {
shader = adoptRef(SkShader::CreateBitmapShader(resampled, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode, &localMatrix));
} else {
shader = adoptRef(SkShader::CreateBitmapShader(
createBitmapWithSpace(resampled, repeatSpacing.width() * ctmScaleX, repeatSpacing.height() * ctmScaleY),
SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode, &localMatrix));
}
} else {
// Because no resizing occurred, the shader transform should be
// set to the pattern's transform, which just includes scale.
localMatrix.preScale(scale.width(), scale.height());
// No need to resample before drawing.
SkBitmap srcSubset;
bitmap().extractSubset(&srcSubset, enclosingIntRect(normSrcRect));
if (repeatSpacing.isZero()) {
shader = adoptRef(SkShader::CreateBitmapShader(srcSubset, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode, &localMatrix));
} else {
shader = adoptRef(SkShader::CreateBitmapShader(
createBitmapWithSpace(srcSubset, repeatSpacing.width() * ctmScaleX, repeatSpacing.height() * ctmScaleY),
SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode, &localMatrix));
}
}
SkPaint paint;
paint.setShader(shader.get());
paint.setXfermodeMode(WebCoreCompositeToSkiaComposite(compositeOp, blendMode));
paint.setColorFilter(context->colorFilter());
paint.setFilterQuality(filterLevel);
context->drawRect(destRect, paint);
}
