小编Don*_*emi的帖子

我能够在HTML画布上成功绘制图像.但我需要能够在画布上拖动图像.

我知道这个函数可以通过一些像KinectJS这样的JavaScript库轻松实现.但我想用简单的JavaScript做到这一点.

window.onload = function(){
var canvas = document.getElementById("myCanvas");
var context = canvas.getContext("2d");
var destX = 0;
var destY = 0;
var imageObj = new Image();

imageObj.onload = function(){
  context.drawImage(imageObj, destX, destY);
};
imageObj.src = "westeros.png";

<canvas id="myCanvas" height=1024 width=360></canvas>

我正在开发一个简单的相机应用 我有代码截取整个活动的截图并将其写入Sd卡.问题是Surfaceview返回黑屏.

我想知道如何独立拍摄surfaceview的截图.这是获取整个活动屏幕截图的代码.

    findViewById(R.id.screen).setOnClickListener(new OnClickListener() {
      @Override
     public void onClick(View v) {
     final RelativeLayout layout = (RelativeLayout) findViewById(R.id.RelativeLayout1);
      layout.setVisibility(RelativeLayout.GONE);
       Bitmap bitmap = takeScreenshot();
        Toast.makeText(getApplicationContext(),"Please Wait",         Toast.LENGTH_LONG).show();
       saveBitmap(bitmap);
   }
});

}



      public Bitmap takeScreenshot() {
       View rootView = findViewById(android.R.id.content).getRootView();
       rootView.setDrawingCacheEnabled(true);
       return rootView.getDrawingCache();
    }


           public void saveBitmap(Bitmap bitmap) {
         final MediaPlayer cheer = MediaPlayer.create(PicShot.this, R.raw.shutter);
       cheer.start();
        Random generator = new Random();
      int n = 10000;
       n = generator.nextInt(n);
        String fname = "Image-"+ n +".png";
      final RelativeLayout layout = (RelativeLayout)     findViewById(R.id.RelativeLayout1);
     File imagePath …

我一直在试图将我的html5画布导出为.gif图像,我能够将其成功保存为.png文件.我知道这里的错误是我的简单代码

canvas.onclick = function () {
window.location = canvas.toDataURL('image/gif');
};