题
我正在画布上绘制2D图像。
我想保存在画布上显示的图像到JPEG文件,我该怎么做?
解决方案
- 创建一个空位图
- 创建一个新的画布对象并将此位图传递给它
- call view.draw(canvas)将其传递给您刚创建的帆布对象。 有关详细信息,请参考方法文档。
- 使用bitmap.compress()将位图的内容写入输出流,也许是文件。
伪代码:
Bitmap bitmap = Bitmap.createBitmap( view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
view.draw(canvas);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
其他提示
- 设置绘图启用缓存
- 画什么你想要的
- 从视图获取位图对象
- 压缩并保存图像文件
import java.io.File;
import java.io.FileOutputStream;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
public class CanvasTest extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Draw2d d = new Draw2d(this);
setContentView(d);
}
public class Draw2d extends View {
public Draw2d(Context context) {
super(context);
setDrawingCacheEnabled(true);
}
@Override
protected void onDraw(Canvas c) {
Paint paint = new Paint();
paint.setColor(Color.RED);
c.drawCircle(50, 50, 30, paint);
try {
getDrawingCache().compress(Bitmap.CompressFormat.JPEG, 100, new FileOutputStream(new File("/mnt/sdcard/arun.jpg")));
} catch (Exception e) {
Log.e("Error--------->", e.toString());
}
super.onDraw(c);
}
}
}
Canvas到JPG:
Canvas canvas = null;
FileOutputStream fos = null;
Bitmap bmpBase = null;
bmpBase = Bitmap.createBitmap(image_width, image_height, Bitmap.Config.ARGB_8888);
canvas = new Canvas(bmpBase);
// draw what ever you want canvas.draw...
// Save Bitmap to File
try
{
fos = new FileOutputStream(your_path);
bmpBase.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.flush();
fos.close();
fos = null;
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
if (fos != null)
{
try
{
fos.close();
fos = null;
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
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