android 的canvas渲染

#define LOG_TAG "VideoCanvas"

#include <android/api-level.h>

#define LOG(...) ((void)0)

#include "utils/log.h"

#include <core/skCanvas.h>

#include <core/SkPaint.h>

#include <core/SkColor.h>

#include <core/SkBitmap.h>

#if __ANDROID_API__ >= 9

#include <surfaceflinger/Surface.h>

#else

#include <ui/Surface.h>

#endif

#include "media_VideoCanvas.h"

using namespace android;

static void* VideoLockCanvas(Surface* native_surface, int *width, int *height, int *stride)

{

    Surface::SurfaceInfo info;

    void *canvasptr = NULL;

    status_t ret = 0;

    ret = native_surface->lock(&info);

    if (ret == OK) {

        canvasptr = info.bits;

        *width = info.w;

        *height = info.h;

        *stride = info.s;

//      LOGI("surface format %d", info.format);

    }

    return canvasptr;

}

static void VideoUnlockCanvas(Surface* native_surface)

{

    native_surface->unlockAndPost();

}

//sp<Surface> surfaceInstance;

static Surface* previous_surface = NULL;

void VideoCanvasSet(void *videocanvas){

    Surface* native_surface = (Surface*)videocanvas;

}

void VideoCanvasDisplay(void *videocanvas, yuv2rgb_cb cb, void* cb_data){

    Surface* native_surface = (Surface*)videocanvas;

    if(native_surface == NULL) {

        return;

    }

    LOGI("enter %p previous %p", native_surface, previous_surface);

    if(native_surface != previous_surface) {

        if(previous_surface != NULL) {

            previous_surface->decStrong((void*)VideoCanvasDisplay); //function name only as id

        }

        native_surface->incStrong((void*)VideoCanvasDisplay);

        previous_surface = native_surface;

    }

    int width, height, stride;

    void* bits = VideoLockCanvas(native_surface, &width, &height, &stride);

    if(bits == NULL) {

        return;

    }

    LOGI("lock %p width %d heigth %d stride %d", bits, width, height, stride);

    cb(cb_data, bits, width, height, stride);

    VideoUnlockCanvas(native_surface);

    LOGI("unlock");

}

/*

 * The only purpose of class "MediaPlayer" is to call Surface::getISurface()

 * in frameworks/base/include/ui/Surface.h, which is private function and accessed

 * by friend class MediaPlayer.

 *

 * We define a fake one to cheat compiler

 */

/*

namespace android {

  class MediaPlayer {

  public:

    static sp < ISurface > getSurface (const Surface * surface){

        if(surface != NULL) {

            return surface->getISurface ();

        }

        return sp < ISurface >;

    };

  };

};

*/

void VideoCanvasClear(void *videocanvas){

    Surface* native_surface = (Surface*)videocanvas;

    if(native_surface == NULL) {

        return;

    }

    LOGI("clear %p previous %p", native_surface, previous_surface);

    if(native_surface != previous_surface) {

        return;

    }

    int width, height, stride;

    void* bits = VideoLockCanvas(native_surface, &width, &height, &stride);

    if(bits == NULL) {

        return;

    }

    LOGI("clear lock %p width %d heigth %d stride %d", bits, width, height, stride);

    memset(bits, 0, stride*height*2);

    VideoUnlockCanvas(native_surface);

    LOGI("clear unlock");

}

void VideoCanvasDestroy(void *videocanvas){

    Surface* native_surface = (Surface*)videocanvas;

    //native_surface->clear();

}

仅供参考！