You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
93 lines
2.9 KiB
93 lines
2.9 KiB
5 years ago
|
---
|
||
|
|
Surface 的绘制原理
|
||
|
|
---
|
||
|
|
|
||
|
|
1. Surface 绘制的 buffer 是怎么来的？
|
||
|
|
2. buffer 绘制完了又是怎么提交的？
|
||
|
|
|
||
|
|
```java
|
||
|
|
private void performTraversals(){
|
||
|
|
performMeasure();
|
||
|
|
performLayout();
|
||
|
|
performDraw();
|
||
|
|
}
|
||
|
|
private void draw(boolean fullRedrawNeeded){
|
||
|
|
Surface surface = mSurface;
|
||
|
|
drawSoftware(surface, mAttachInfo, ..., dirty);
|
||
|
|
}
|
||
|
|
private boolean drawSoftware(Surface surface, ...){
|
||
|
|
final Canvas canvas;
|
||
|
|
canvas = mSurface.lockCanvas(dirty);
|
||
|
|
mView.draw(canvas);
|
||
|
|
surface.unlockCanvasAndPost(canvas);
|
||
|
|
}
|
||
|
|
static jlong nativeLockCanvas(JNIEnv* env, jclass clazz, jlong nativeObject, jobject canvasObj, jobject dirtyRectObj){
|
||
|
|
sp<Surface> surface(reinterpert_cast<Surface *>(nativeObject));
|
||
|
|
ANativeWindow_Buffer outBuffer;
|
||
|
|
surface->lock(&outBuffer, dirtyRectPtr);
|
||
|
|
SkBitmap bitmap;
|
||
|
|
bitmap.setPixels(outBuffer.bits);
|
||
|
|
Canvas* nativeCanvas = GraphicsJNI::getNativeCanvas(env, canvasObj);
|
||
|
|
nativeCanvas->setBitmap(bitmap);
|
||
|
|
sp<Surface> lockedSurface(surface);
|
||
|
|
return (jlong)lockedSurface.get();
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
每次绘制都要重新申请一块 buffer，它是怎么申请的？
|
||
|
|
|
||
|
|
```c++
|
||
|
|
status_t Surface::lock(ANativeWindow_Buffer* outBuffer, ...){
|
||
|
|
ANativeWindowBuffer* out;
|
||
|
|
dequeueBuffer(&out, &fenceFd);
|
||
|
|
sp<GraphicBuffer> backBuffer(GraphicBuffer::getSelf(out));
|
||
|
|
void* vaddr;
|
||
|
|
status_t res = backBuffer->lockAsync(..., &vaddr, fenceFd);
|
||
|
|
mLockedBuffer = backBuffer;
|
||
|
|
outBuffer->bits = vaddr;
|
||
|
|
}
|
||
|
|
int Surface::dequeueBuffer(android_native_buffer_t** buffer, ...){
|
||
|
|
int buf = -1;
|
||
|
|
status_t result = mGraphicBufferProduct->dequeueBuffer(&buf, ...);
|
||
|
|
sp<GraphicBuffer>& gbuf(mSlot[buf].buffer);
|
||
|
|
if((result&IGraphicBufferProduct::BUFFER_NEEDS_REALLOCATION)||gbuf == 0){
|
||
|
|
result = mGraphicBufferProduct->requestBuffer(buf, &gbuf);
|
||
|
|
}
|
||
|
|
*buffer = gbuf.get();
|
||
|
|
return OK;
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
Buffer 是怎么提交的？
|
||
|
|
|
||
|
|
```c++
|
||
|
|
public void unlockCanvasAndPost(Canvas canvas){
|
||
|
|
synchronized(mLock){
|
||
|
|
unlockSwCanvasAndPost(canvas);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
private void unlockSwCanvasAndPost(Canvas canvas){
|
||
|
|
nativeUnlockCanvasAndPost(mLockedObject, canvas);
|
||
|
|
nativeRelease(mLockedObject);
|
||
|
|
mLockedObject = 0;
|
||
|
|
}
|
||
|
|
static void nativeUnlockCanvasAndPost(JNIEnv* env, jclass clazz, jlong nativeObject, jobject canvasObj) {
|
||
|
|
sp<Surface> surface(reinterpret_cast<Surface *>(nativeObject));
|
||
|
|
Canvas* nativeCanvas = GraphicsJNI::getNativeCanvas(env, canvasObj);
|
||
|
|
nativeCanvas->setBitmap(SkBitmap());
|
||
|
|
surface->unlockAndPost();
|
||
|
|
}
|
||
|
|
status_t Surface::unlockAndPost(){
|
||
|
|
mLockedBuffer->unlockAsync(...);
|
||
|
|
queueBuffer(mLockedBuffer.get(), ...);
|
||
|
|
mPostedBuffer = mLockedBuffer;
|
||
|
|
mLockedBuffer = 0;
|
||
|
|
return err;
|
||
|
|
}
|
||
|
|
int Surface::queueBuffer(android_native_buffer_t* buffer, ...){
|
||
|
|
int i = getSlotFromBufferLocked(buffer);
|
||
|
|
mGraphicBufferProducer->queueBuffer(i, ...);
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
|