src\third_party\skia\docs\examples
在 gpu 上繪製,然後用surface的snapshot獲取 圖片;
skimage也可以直接從texture
// Copyright 2019 Google LLC.
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
#include "tools/fiddle/examples.h"
// HASH=06aeb3cf63ffccf7b49fe556e5def351
REG_FIDDLE(Image_MakeBackendTextureFromSkImage, 256, 64, false, 0) {
static sk_sp<SkImage> create_gpu_image(GrRecordingContext* rContext) {
// rContext 是個gpu繪製上下文
const SkImageInfo info = SkImageInfo::MakeN32(20, 20, kOpaque_SkAlphaType);
auto surface(SkSurface::MakeRenderTarget(rContext, SkBudgeted::kNo, info));
//通過canvas繪製,繪製在gpu進行
SkCanvas* canvas = surface->getCanvas();
canvas->clear(SK_ColorWHITE);
SkPaint paint;
paint.setColor(SK_ColorBLACK);
canvas->drawRect(SkRect::MakeXYWH(5, 5, 10, 10), paint);
//獲取剛纔繪製的圖片
return surface->makeImageSnapshot();
}
void draw(SkCanvas* canvas) {
auto dContext = GrAsDirectContext(canvas->recordingContext());
if (!dContext) {
return;
}
sk_sp<SkImage> backEndImage = create_gpu_image(dContext);
canvas->drawImage(backEndImage, 0, 0);
//將圖片繪製到gpu的texture上
GrBackendTexture texture;
SkImage::BackendTextureReleaseProc proc;
if (!SkImage::MakeBackendTextureFromSkImage(dContext, std::move(backEndImage),
&texture, &proc)) {
return;
}
//從texture繪製獲取成skimage圖片。
sk_sp<SkImage> i2 = SkImage::MakeFromTexture(dContext, texture, kTopLeft_GrSurfaceOrigin,
kN32_SkColorType, kOpaque_SkAlphaType, nullptr);
canvas->drawImage(i2, 30, 30);
}
} // END FIDDLE