SkImageSource

src/effects/SkImageSource.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkImageSource.h"
+
+#include "SkCanvas.h"
+#include "SkDevice.h"
+#include "SkImage.h"
+#include "SkReadBuffer.h"
+#include "SkWriteBuffer.h"
+#include "SkString.h"
+
+SkImageSource* SkImageSource::Create(const SkImage* image) {
+    return image ? SkNEW_ARGS(SkImageSource, (image)) : nullptr;
+}
+
+SkImageSource* SkImageSource::Create(const SkImage* image,
+                                     const SkRect& srcRect,
+                                     const SkRect& dstRect,
+                                     SkFilterQuality filterQuality) {
+    return image ? SkNEW_ARGS(SkImageSource, (image, srcRect, dstRect, filterQuality)) : nullptr;
+}
+
+SkImageSource::SkImageSource(const SkImage* image)
+    : INHERITED(0, 0)
+    , fImage(SkRef(image))
+    , fSrcRect(SkRect::MakeIWH(image->width(), image->height()))
+    , fDstRect(fSrcRect)
+    , fFilterQuality(kHigh_SkFilterQuality) { }
+
+SkImageSource::SkImageSource(const SkImage* image,
+                             const SkRect& srcRect,
+                             const SkRect& dstRect,
+                             SkFilterQuality filterQuality)
+    : INHERITED(0, 0)
+    , fImage(SkRef(image))
+    , fSrcRect(srcRect)
+    , fDstRect(dstRect)
+    , fFilterQuality(filterQuality) { }
+
+SkFlattenable* SkImageSource::CreateProc(SkReadBuffer& buffer) {
+    SkFilterQuality filterQuality = (SkFilterQuality)buffer.readInt();
+
+    SkRect src, dst;
+    buffer.readRect(&src);
+    buffer.readRect(&dst);
+
+    SkAutoTUnref<SkImage> image(buffer.readImage());
+    if (image) {
+        return nullptr;
+    }
+
+    return SkImageSource::Create(image, src, dst, filterQuality);
+}
+
+void SkImageSource::flatten(SkWriteBuffer& buffer) const {
+    buffer.writeInt(fFilterQuality);
+    buffer.writeRect(fSrcRect);
+    buffer.writeRect(fDstRect);
+    buffer.writeImage(fImage);
+}
+
+bool SkImageSource::onFilterImage(Proxy* proxy, const SkBitmap& src, const Context& ctx,
+                                  SkBitmap* result, SkIPoint* offset) const {
+    SkRect dstRect;
+    ctx.ctm().mapRect(&dstRect, fDstRect);
+    SkRect bounds = SkRect::MakeIWH(fImage->width(), fImage->height());
+    if (fSrcRect == bounds && dstRect == bounds) {
+        // No regions cropped out or resized; return entire image.
+        offset->fX = offset->fY = 0;
+        return fImage->asLegacyBitmap(result, SkImage::kRW_LegacyBitmapMode);

[f(malita), 2015/09/14 18:16:57]

Can the result be RO/immutable?

+    }
+
+    const SkIRect dstIRect = dstRect.roundOut();
+    SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(dstIRect.width(), dstIRect.height()));
+    if (nullptr == device.get()) {
+        return false;
+    }
+
+    SkCanvas canvas(device.get());
+    SkPaint paint;
+
+    // Subtract off the integer component of the translation (will be applied in loc, below).
+    dstRect.offset(-SkIntToScalar(dstIRect.fLeft), -SkIntToScalar(dstIRect.fTop));
+    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
+    // FIXME: this probably shouldn't be necessary, but drawImageRect asserts
+    // None filtering when it's translate-only
+    paint.setFilterQuality(
+        fSrcRect.width() == dstRect.width() && fSrcRect.height() == dstRect.height() ?
+               kNone_SkFilterQuality : fFilterQuality);
+    canvas.drawImageRect(fImage, fSrcRect, dstRect, &paint, SkCanvas::kStrict_SrcRectConstraint);
+
+    *result = device.get()->accessBitmap(false);
+    offset->fX = dstIRect.fLeft;
+    offset->fY = dstIRect.fTop;
+
+    return true;
+}
+
+void SkImageSource::computeFastBounds(const SkRect& src, SkRect* dst) const {
+    *dst = fDstRect;
+}
+
+#ifndef SK_IGNORE_TO_STRING
+void SkImageSource::toString(SkString* str) const {
+    str->appendf("SkImageSource: (");
+    str->appendf("src: (%f,%f,%f,%f) dst: (%f,%f,%f,%f) ",
+                 fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom,
+                 fDstRect.fLeft, fDstRect.fTop, fDstRect.fRight, fDstRect.fBottom);
+    str->appendf("image: (%d,%d)",
+                 fImage->width(), fImage->height());
+    str->append(")");
+}
+#endif