void
NinePatchGlue::drawStretchyPatch(SkCanvas& canvas, SkIRect& src, const SkRect& dst,
const BitmapGlue& bitmap, const PaintGlue& paint,
SkColor initColor, uint32_t colorHint,
bool hasXfer)
{
if (colorHint != Res_png_9patch::NO_COLOR) {
((PaintGlue*)&paint)->setColor(modAlpha(colorHint, paint.getAlpha()));
canvas.drawRect(dst, paint);
((PaintGlue*)&paint)->setColor(initColor);
} else if (src.width() == 1 && src.height() == 1) {
SkColor c;
if (!getColor(bitmap, src.fLeft, src.fTop, &c)) {
goto SLOW_CASE;
}
if (0 != c || hasXfer) {
SkColor prev = paint.getColor();
((PaintGlue*)&paint)->setColor(c);
canvas.drawRect(dst, paint);
((PaintGlue*)&paint)->setColor(prev);
}
} else {
SLOW_CASE:
canvas.drawBitmapRect(bitmap, &src, dst, &paint);
}
}
void paint(GraphicsContext* ctxt, const IntRect& r)
{
if (ctxt->paintingDisabled())
return;
if (!m_isVisible)
return;
if (!m_poster || (!m_poster->getPixels() && !m_poster->pixelRef()))
return;
SkCanvas* canvas = ctxt->platformContext()->getCanvas();
if (!canvas)
return;
// We paint with the following rules in mind:
// - only downscale the poster, never upscale
// - maintain the natural aspect ratio of the poster
// - the poster should be centered in the target rect
float originalRatio = static_cast<float>(m_poster->width()) / static_cast<float>(m_poster->height());
int posterWidth = r.width() > m_poster->width() ? m_poster->width() : r.width();
int posterHeight = posterWidth / originalRatio;
int posterX = ((r.width() - posterWidth) / 2) + r.x();
int posterY = ((r.height() - posterHeight) / 2) + r.y();
IntRect targetRect(posterX, posterY, posterWidth, posterHeight);
canvas->drawBitmapRect(*m_poster, 0, targetRect, 0);
}
static void paintSkBitmap(PlatformContextSkia* platformContext, const NativeImageSkia& bitmap, const SkIRect& srcRect, const SkRect& destRect, const SkXfermode::Mode& compOp)
{
SkPaint paint;
paint.setXfermodeMode(compOp);
paint.setFilterBitmap(true);
paint.setAlpha(platformContext->getNormalizedAlpha());
paint.setLooper(platformContext->getDrawLooper());
// only antialias if we're rotated or skewed
paint.setAntiAlias(hasNon90rotation(platformContext));
SkCanvas* canvas = platformContext->canvas();
ResamplingMode resampling;
if (platformContext->isAccelerated())
resampling = RESAMPLE_LINEAR;
else
resampling = platformContext->printing() ? RESAMPLE_NONE :
computeResamplingMode(platformContext, bitmap, srcRect.width(), srcRect.height(), SkScalarToFloat(destRect.width()), SkScalarToFloat(destRect.height()));
if (resampling == RESAMPLE_AWESOME) {
drawResampledBitmap(*canvas, paint, bitmap, srcRect, destRect);
} else {
// No resampling necessary, we can just draw the bitmap. We want to
// filter it if we decided to do linear interpolation above, or if there
// is something interesting going on with the matrix (like a rotation).
// Note: for serialization, we will want to subset the bitmap first so
// we don't send extra pixels.
canvas->drawBitmapRect(bitmap.bitmap(), &srcRect, destRect, &paint);
}
}
ImageTexture::ImageTexture(SkBitmapRef* img)
: m_imageRef(img)
, m_image(0)
, m_textureId(0)
, m_refCount(0)
{
#ifdef DEBUG_COUNT
ClassTracker::instance()->increment("ImageTexture");
#endif
if (!m_imageRef)
return;
SkBitmap* bitmap = &m_imageRef->bitmap();
m_image = new SkBitmap();
int w = bitmap->width();
int h = bitmap->height();
m_image->setConfig(SkBitmap::kARGB_8888_Config, w, h);
m_image->allocPixels();
SkDevice* device = new SkDevice(NULL, *m_image, false);
SkCanvas canvas;
canvas.setDevice(device);
device->unref();
SkRect dest;
dest.set(0, 0, w, h);
m_image->setIsOpaque(false);
m_image->eraseARGB(0, 0, 0, 0);
canvas.drawBitmapRect(*bitmap, 0, dest);
}
void TransparencyWin::compositeTextComposite()
{
if (!m_validLayer)
return;
const SkBitmap& bitmap = m_layerBuffer->context()->platformContext()->canvas()->getTopDevice()->accessBitmap(true);
SkColor textColor = m_textCompositeColor.rgb();
for (int y = 0; y < m_layerSize.height(); y++) {
uint32_t* row = bitmap.getAddr32(0, y);
for (int x = 0; x < m_layerSize.width(); x++) {
// The alpha is the average of the R, G, and B channels.
int alpha = (SkGetPackedR32(row[x]) + SkGetPackedG32(row[x]) + SkGetPackedB32(row[x])) / 3;
// Apply that alpha to the text color and write the result.
row[x] = SkAlphaMulQ(textColor, SkAlpha255To256(255 - alpha));
}
}
// Now the layer has text with the proper color and opacity.
SkCanvas* destCanvas = canvasForContext(*m_destContext);
destCanvas->save();
// We want to use Untransformed space (see above)
SkMatrix identity;
identity.reset();
destCanvas->setMatrix(identity);
SkRect destRect = { m_transformedSourceRect.x(), m_transformedSourceRect.y(), m_transformedSourceRect.maxX(), m_transformedSourceRect.maxY() };
// Note that we need to specify the source layer subset, since the bitmap
// may have been cached and it could be larger than what we're using.
SkIRect sourceRect = { 0, 0, m_layerSize.width(), m_layerSize.height() };
destCanvas->drawBitmapRect(bitmap, &sourceRect, destRect, 0);
destCanvas->restore();
}
// 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 TransparencyWin::compositeOpaqueComposite()
{
if (!m_validLayer)
return;
SkCanvas* destCanvas = canvasForContext(*m_destContext);
destCanvas->save();
SkBitmap* bitmap = const_cast<SkBitmap*>(
&bitmapForContext(*m_layerBuffer->context()));
// This function will be called for WhiteLayer as well, which we don't want
// to change.
if (m_layerMode == OpaqueCompositeLayer) {
// Fix up our bitmap, making it contain only the pixels which changed
// and transparent everywhere else.
SkAutoLockPixels sourceLock(*m_referenceBitmap);
SkAutoLockPixels lock(*bitmap);
for (int y = 0; y < bitmap->height(); y++) {
uint32_t* source = m_referenceBitmap->getAddr32(0, y);
uint32_t* dest = bitmap->getAddr32(0, y);
for (int x = 0; x < bitmap->width(); x++) {
// Clear out any pixels that were untouched.
if (dest[x] == source[x])
dest[x] = 0;
else
dest[x] |= (0xFF << SK_A32_SHIFT);
}
}
} else
makeLayerOpaque();
SkRect destRect;
if (m_transformMode != Untransform) {
// We want to use Untransformed space.
//
// Note that we DON'T call m_layerBuffer->image() here. This actually
// makes a copy of the image, which is unnecessary and slow. Instead, we
// just draw the image from inside the destination context.
SkMatrix identity;
identity.reset();
destCanvas->setMatrix(identity);
destRect.set(m_transformedSourceRect.x(), m_transformedSourceRect.y(), m_transformedSourceRect.maxX(), m_transformedSourceRect.maxY());
} else
destRect.set(m_sourceRect.x(), m_sourceRect.y(), m_sourceRect.maxX(), m_sourceRect.maxY());
SkPaint paint;
paint.setFilterBitmap(true);
paint.setAntiAlias(true);
// Note that we need to specify the source layer subset, since the bitmap
// may have been cached and it could be larger than what we're using.
SkIRect sourceRect = { 0, 0, m_layerSize.width(), m_layerSize.height() };
destCanvas->drawBitmapRect(*bitmap, &sourceRect, destRect, &paint);
destCanvas->restore();
}
DEF_TEST(IndexedPngOverflow, reporter) {
SkBitmap image;
bool success = decode_memory(gPng, sizeof(gPng), &image);
REPORTER_ASSERT(reporter, success);
SkAutoTUnref<SkSurface> surface(SkSurface::NewRaster(SkImageInfo::MakeN32Premul(20, 1)));
SkCanvas* canvas = surface->getCanvas();
SkRect destRect = SkRect::MakeXYWH(0, 0, 20, 1);
canvas->drawBitmapRect(image, destRect, nullptr);
}
void BitmapImage::draw(GraphicsContext* ctxt, const FloatRect& dstRect,
const FloatRect& srcRect, CompositeOperator compositeOp)
{
startAnimation();
SkBitmapRef* image = this->nativeImageForCurrentFrame();
if (!image) { // If it's too early we won't have an image yet.
return;
}
// in case we get called with an incomplete bitmap
const SkBitmap& bitmap = image->bitmap();
if (bitmap.getPixels() == NULL && bitmap.pixelRef() == NULL) {
#ifdef TRACE_SKIPPED_BITMAPS
SkDebugf("----- skip bitmapimage: [%d %d] pixels %p pixelref %p\n",
bitmap.width(), bitmap.height(),
bitmap.getPixels(), bitmap.pixelRef());
#endif
return;
}
SkIRect srcR;
SkRect dstR;
float invScaleX = (float)bitmap.width() / image->origWidth();
float invScaleY = (float)bitmap.height() / image->origHeight();
android_setrect(&dstR, dstRect);
android_setrect_scaled(&srcR, srcRect, invScaleX, invScaleY);
if (srcR.isEmpty() || dstR.isEmpty()) {
#ifdef TRACE_SKIPPED_BITMAPS
SkDebugf("----- skip bitmapimage: [%d %d] src-empty %d dst-empty %d\n",
bitmap.width(), bitmap.height(),
srcR.isEmpty(), dstR.isEmpty());
#endif
return;
}
SkCanvas* canvas = ctxt->platformContext()->mCanvas;
SkPaint paint;
paint.setFilterBitmap(true);
paint.setPorterDuffXfermode(android_convert_compositeOp(compositeOp));
canvas->drawBitmapRect(bitmap, &srcR, dstR, &paint);
#ifdef TRACE_SUBSAMPLED_BITMAPS
if (bitmap.width() != image->origWidth() ||
bitmap.height() != image->origHeight()) {
SkDebugf("--- BitmapImage::draw [%d %d] orig [%d %d]\n",
bitmap.width(), bitmap.height(),
image->origWidth(), image->origHeight());
}
#endif
}
static void paintSkBitmap(PlatformContextSkia* platformContext, const NativeImageSkia& bitmap, const SkIRect& srcRect, const SkRect& destRect, const SkXfermode::Mode& compOp)
{
#if PLATFORM(CHROMIUM)
TRACE_EVENT0("skia", "paintSkBitmap");
#endif
SkPaint paint;
paint.setXfermodeMode(compOp);
paint.setAlpha(platformContext->getNormalizedAlpha());
paint.setLooper(platformContext->getDrawLooper());
// only antialias if we're rotated or skewed
paint.setAntiAlias(hasNon90rotation(platformContext));
SkCanvas* canvas = platformContext->canvas();
ResamplingMode resampling;
if (platformContext->isAccelerated())
resampling = RESAMPLE_LINEAR;
else if (platformContext->printing())
resampling = RESAMPLE_NONE;
else {
// Take into account scale applied to the canvas when computing sampling mode (e.g. CSS scale or page scale).
SkRect destRectTarget = destRect;
if (!(canvas->getTotalMatrix().getType() & (SkMatrix::kAffine_Mask | SkMatrix::kPerspective_Mask)))
canvas->getTotalMatrix().mapRect(&destRectTarget, destRect);
resampling = computeResamplingMode(canvas->getTotalMatrix(), bitmap, srcRect.width(), srcRect.height(),
SkScalarToFloat(destRectTarget.width()), SkScalarToFloat(destRectTarget.height()));
}
if (resampling == RESAMPLE_NONE) {
// FIXME: This is to not break tests (it results in the filter bitmap flag
// being set to true). We need to decide if we respect RESAMPLE_NONE
// being returned from computeResamplingMode.
resampling = RESAMPLE_LINEAR;
}
resampling = limitResamplingMode(platformContext, resampling);
paint.setFilterBitmap(resampling == RESAMPLE_LINEAR);
if (resampling == RESAMPLE_AWESOME)
drawResampledBitmap(*canvas, paint, bitmap, srcRect, destRect);
else {
// No resampling necessary, we can just draw the bitmap. We want to
// filter it if we decided to do linear interpolation above, or if there
// is something interesting going on with the matrix (like a rotation).
// Note: for serialization, we will want to subset the bitmap first so
// we don't send extra pixels.
canvas->drawBitmapRect(bitmap.bitmap(), &srcRect, destRect, &paint);
}
platformContext->didDrawRect(destRect, paint, &bitmap.bitmap());
}
// Draws the given bitmap to the given canvas. The subset of the source bitmap
// identified by src_rect is drawn to the given destination rect. The bitmap
// will be resampled to resample_width * resample_height (this is the size of
// the whole image, not the subset). See shouldResampleBitmap for more.
//
// 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 SkIRect& srcIRect, const SkRect& destRect)
{
#if PLATFORM(CHROMIUM)
TRACE_EVENT0("skia", "drawResampledBitmap");
#endif
// Apply forward transform to destRect to estimate required size of
// re-sampled bitmap, and use only in calls required to resize, or that
// check for the required size.
SkRect destRectTransformed;
canvas.getTotalMatrix().mapRect(&destRectTransformed, destRect);
SkIRect destRectTransformedRounded;
destRectTransformed.round(&destRectTransformedRounded);
// Compute the visible portion of our rect.
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.
// Compute the image-relative (bitmap space) subset.
SkRect destBitmapSubset = destRectVisibleSubset;
destBitmapSubset.offset(-destRect.x(), -destRect.y());
// Scale the subset to the requested size. The canvas scale can be negative,
// but the resampling code is only interested in positive scaling in its normal space.
SkMatrix subsetTransform;
subsetTransform.setScale(SkScalarAbs(canvas.getTotalMatrix().getScaleX()),
SkScalarAbs(canvas.getTotalMatrix().getScaleY()));
SkRect destBitmapSubsetTransformed;
subsetTransform.mapRect(&destBitmapSubsetTransformed, destBitmapSubset);
SkIRect destBitmapSubsetTransformedRounded;
destBitmapSubsetTransformed.round(&destBitmapSubsetTransformedRounded);
// Transforms above plus rounding may cause destBitmapSubsetTransformedRounded
// to go outside the image, so need to clip to avoid problems.
if (!destBitmapSubsetTransformedRounded.intersect(
0, 0, destRectTransformedRounded.width(), destRectTransformedRounded.height()))
return; // Image is not visible.
SkBitmap resampled = bitmap.resizedBitmap(srcIRect,
destRectTransformedRounded.width(),
destRectTransformedRounded.height(),
destBitmapSubsetTransformedRounded);
canvas.drawBitmapRect(resampled, 0, destRectVisibleSubset, &paint);
}
// Draws the given bitmap to the given canvas. The subset of the source bitmap
// identified by src_rect is drawn to the given destination rect. The bitmap
// will be resampled to resample_width * resample_height (this is the size of
// the whole image, not the subset). See shouldResampleBitmap for more.
//
// 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 SkIRect& srcIRect, const SkRect& destRect)
{
#if PLATFORM(CHROMIUM)
TRACE_EVENT("drawResampledBitmap", &canvas, 0);
#endif
// Apply forward transform to destRect to estimate required size of
// re-sampled bitmap, and use only in calls required to resize, or that
// check for the required size.
SkRect destRectTransformed;
canvas.getTotalMatrix().mapRect(&destRectTransformed, destRect);
SkIRect destRectTransformedRounded;
destRectTransformed.round(&destRectTransformedRounded);
// Compute the visible portion of our rect.
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.
// Compute the transformed (screen space) portion of the visible portion for
// use below.
SkRect destRectVisibleSubsetTransformed;
canvas.getTotalMatrix().mapRect(&destRectVisibleSubsetTransformed, destRectVisibleSubset);
SkRect destBitmapSubsetTransformed = destRectVisibleSubsetTransformed;
destBitmapSubsetTransformed.offset(-destRectTransformed.fLeft,
-destRectTransformed.fTop);
SkIRect destBitmapSubsetTransformedRounded;
destBitmapSubsetTransformed.round(&destBitmapSubsetTransformedRounded);
// Transforms above plus rounding may cause destBitmapSubsetTransformedRounded
// to go outside the image, so need to clip to avoid problems.
if (!destBitmapSubsetTransformedRounded.intersect(
0, 0, destRectTransformedRounded.width(), destRectTransformedRounded.height()))
return; // Image is not visible.
SkBitmap resampled = bitmap.resizedBitmap(srcIRect,
destRectTransformedRounded.width(),
destRectTransformedRounded.height(),
destBitmapSubsetTransformedRounded);
canvas.drawBitmapRect(resampled, 0, destRectVisibleSubset, &paint);
}
void renderer_item_image::draw_graphics_item (SkCanvas &canvas, const renderer_state &/*state*/, const renderer_config *config) const
{
SkBitmap bitmap = qt2skia::image (m_image_data);
SkPaint paint;
paint.setAlpha ((int) (m_opacity * 255));
if (config->render_for_selection ())
{
if (!configure_painter_for_selection (paint))
return;
canvas.drawRect (qt2skia::rect (m_dst_rect), paint);
}
else
{
if (!bitmap.isNull ())
{
SkIRect irect = qt2skia::Irect (m_src_rect);
canvas.drawBitmapRect (bitmap, &irect, qt2skia::rect (m_dst_rect), &paint);
}
}
}
// Test out SkPictureRecorder::partialReplay
DEF_TEST(PictureRecorder_replay, reporter) {
// check save/saveLayer state
{
SkPictureRecorder recorder;
SkCanvas* canvas = recorder.beginRecording(10, 10);
canvas->saveLayer(nullptr, nullptr);
sk_sp<SkPicture> copy(SkPictureRecorderReplayTester::Copy(&recorder));
// The extra save and restore comes from the Copy process.
check_save_state(reporter, copy.get(), 2, 1, 3);
canvas->saveLayer(nullptr, nullptr);
sk_sp<SkPicture> final(recorder.finishRecordingAsPicture());
check_save_state(reporter, final.get(), 1, 2, 3);
// The copy shouldn't pick up any operations added after it was made
check_save_state(reporter, copy.get(), 2, 1, 3);
}
// (partially) check leakage of draw ops
{
SkPictureRecorder recorder;
SkCanvas* canvas = recorder.beginRecording(10, 10);
SkRect r = SkRect::MakeWH(5, 5);
SkPaint p;
canvas->drawRect(r, p);
sk_sp<SkPicture> copy(SkPictureRecorderReplayTester::Copy(&recorder));
REPORTER_ASSERT(reporter, !copy->willPlayBackBitmaps());
SkBitmap bm;
make_bm(&bm, 10, 10, SK_ColorRED, true);
r.offset(5.0f, 5.0f);
canvas->drawBitmapRect(bm, r, nullptr);
sk_sp<SkPicture> final(recorder.finishRecordingAsPicture());
REPORTER_ASSERT(reporter, final->willPlayBackBitmaps());
REPORTER_ASSERT(reporter, copy->uniqueID() != final->uniqueID());
// The snapshot shouldn't pick up any operations added after it was made
REPORTER_ASSERT(reporter, !copy->willPlayBackBitmaps());
}
// Recreate the Android partialReplay test case
{
SkPictureRecorder recorder;
SkCanvas* canvas = recorder.beginRecording(4, 3, nullptr, 0);
create_imbalance(canvas);
int expectedSaveCount = canvas->getSaveCount();
sk_sp<SkPicture> copy(SkPictureRecorderReplayTester::Copy(&recorder));
check_balance(reporter, copy.get());
REPORTER_ASSERT(reporter, expectedSaveCount = canvas->getSaveCount());
// End the recording of source to test the picture finalization
// process isn't complicated by the partialReplay step
sk_sp<SkPicture> final(recorder.finishRecordingAsPicture());
}
}
// Draws the given bitmap to the given canvas. The subset of the source bitmap
// identified by src_rect is drawn to the given destination rect. The bitmap
// will be resampled to resample_width * resample_height (this is the size of
// the whole image, not the subset). See shouldResampleBitmap for more.
//
// 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.
static void drawResampledBitmap(SkCanvas& canvas, SkPaint& paint, const NativeImageSkia& bitmap, const SkIRect& srcIRect, const SkRect& destRect)
{
// First get the subset we need. This is efficient and does not copy pixels.
SkBitmap subset;
bitmap.extractSubset(&subset, srcIRect);
SkRect srcRect;
srcRect.set(srcIRect);
// Whether we're doing a subset or using the full source image.
bool srcIsFull = srcIRect.fLeft == 0 && srcIRect.fTop == 0
&& srcIRect.width() == bitmap.width()
&& srcIRect.height() == bitmap.height();
// We will always draw in integer sizes, so round the destination rect.
SkIRect destRectRounded;
destRect.round(&destRectRounded);
SkIRect resizedImageRect = // Represents the size of the resized image.
{ 0, 0, destRectRounded.width(), destRectRounded.height() };
if (srcIsFull && bitmap.hasResizedBitmap(destRectRounded.width(), destRectRounded.height())) {
// Yay, this bitmap frame already has a resized version.
SkBitmap resampled = bitmap.resizedBitmap(destRectRounded.width(), destRectRounded.height());
canvas.drawBitmapRect(resampled, 0, destRect, &paint);
return;
}
// Compute the visible portion of our rect.
SkRect destBitmapSubsetSk;
ClipRectToCanvas(canvas, destRect, &destBitmapSubsetSk);
destBitmapSubsetSk.offset(-destRect.fLeft, -destRect.fTop);
// The matrix inverting, etc. could have introduced rounding error which
// causes the bounds to be outside of the resized bitmap. We round outward
// so we always lean toward it being larger rather than smaller than we
// need, and then clamp to the bitmap bounds so we don't get any invalid
// data.
SkIRect destBitmapSubsetSkI;
destBitmapSubsetSk.roundOut(&destBitmapSubsetSkI);
if (!destBitmapSubsetSkI.intersect(resizedImageRect))
return; // Resized image does not intersect.
if (srcIsFull && bitmap.shouldCacheResampling(
resizedImageRect.width(),
resizedImageRect.height(),
destBitmapSubsetSkI.width(),
destBitmapSubsetSkI.height())) {
// We're supposed to resize the entire image and cache it, even though
// we don't need all of it.
SkBitmap resampled = bitmap.resizedBitmap(destRectRounded.width(),
destRectRounded.height());
canvas.drawBitmapRect(resampled, 0, destRect, &paint);
} else {
// We should only resize the exposed part of the bitmap to do the
// minimal possible work.
// Resample the needed part of the image.
SkBitmap resampled = skia::ImageOperations::Resize(subset,
skia::ImageOperations::RESIZE_LANCZOS3,
destRectRounded.width(), destRectRounded.height(),
destBitmapSubsetSkI);
// Compute where the new bitmap should be drawn. Since our new bitmap
// may be smaller than the original, we have to shift it over by the
// same amount that we cut off the top and left.
destBitmapSubsetSkI.offset(destRect.fLeft, destRect.fTop);
SkRect offsetDestRect;
offsetDestRect.set(destBitmapSubsetSkI);
canvas.drawBitmapRect(resampled, 0, offsetDestRect, &paint);
}
}
