android 图片效果相关

通过矩形生成缩略图

public static Bitmap createBitmapThumbnail(Bitmap bitmap, int width,

            int height) {
        final int bitmapWidth = bitmap.getWidth();
        final int bitmapHeight = bitmap.getHeight();

        if (width > 0 && height > 0) {

            final Bitmap.Config c = Bitmap.Config.ARGB_8888;
            final Bitmap thumb = Bitmap.createBitmap(width, height, c);
            final Canvas canvas = new Canvas();
            final Paint paint = new Paint();

            canvas.setBitmap(thumb);
            paint.setDither(false);
            paint.setFilterBitmap(true);
            Rect sBounds = new Rect();
            sBounds.set(0, 0, width, height);
            Rect sOldBounds = new Rect();
            sOldBounds.set(0, 0, bitmapWidth, bitmapHeight);
            canvas.drawBitmap(bitmap, sOldBounds, sBounds, paint);
            
            return thumb;
        }

        return bitmap;
    }

   

通过矩阵生成缩略图

public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){

        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        Matrix matrix = new Matrix();
        float scaleWidht = ((float)w / width);
        float scaleHeight = ((float)h / height);
        matrix.postScale(scaleWidht, scaleHeight);
        Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
        return newbmp;

    }

从drawable生成bitmap

public static Bitmap drawable2Bitmap(Drawable drawable) {
        try {
            int width = drawable.getIntrinsicWidth();
            int height = drawable.getIntrinsicHeight();
            Bitmap.Config config = Bitmap.Config.ARGB_8888; //RGB565绘制会有黑边�?
            Bitmap bitmap = Bitmap.createBitmap(width, height, config);
            Canvas canvas = new Canvas(bitmap);
            drawable.setBounds(0, 0, width, height);
            drawable.draw(canvas);
            return bitmap;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

从视图生成bitmap

public static Bitmap view2Bitmap(View v) {
        v.clearFocus();
        v.setPressed(false);

        boolean willNotCache = v.willNotCacheDrawing();
        v.setWillNotCacheDrawing(false);

        // Reset the drawing cache background color to fully transparent
        // for the duration of this operation
        int color = v.getDrawingCacheBackgroundColor();
        v.setDrawingCacheBackgroundColor(0);

        if (color != 0) {
            v.destroyDrawingCache();
        }
        v.buildDrawingCache();
        Bitmap cacheBitmap = v.getDrawingCache();
        if (cacheBitmap == null) {
            return null;
        }

        Bitmap bitmap = Bitmap.createBitmap(cacheBitmap);

        // Restore the view
        v.destroyDrawingCache();
        v.setWillNotCacheDrawing(willNotCache);
        v.setDrawingCacheBackgroundColor(color);
        
        //Bitmap bitmap1 = setAlpha(bitmap, 100);

        return bitmap;
    }

图片合成

private Bitmap createBitmap（ Bitmap src， Bitmap watermark ） {
if（ src == null ） {
return null;
}
int w = src.getWidth（）;
int h = src.getHeight（）;
int ww = watermark.getWidth（）;
int wh = watermark.getHeight（）;
//create the new blank bitmap
Bitmap newb = Bitmap.createBitmap（ w， h， Config.ARGB_8888 ）;//创建一个新的和SRC长度宽度一样的位图
Canvas cv = new Canvas（ newb ）;
//draw src into
cv.drawBitmap（ src， 0， 0， null ）;//在 0，0坐标开端画入src
//draw watermark into
cv.drawBitmap（ watermark， w - ww + 5， h - wh + 5， null ）;//在src的右下角画入水印
//save all clip
cv.save（ Canvas.ALL_SAVE_FLAG ）;//保存
//store
cv.restore（）;//存储
return newb;
}

图片圆角

public static Bitmap getRoundedCornerBitmap（Bitmap bitmap） {
Bitmap output = Bitmap.createBitmap（bitmap.getWidth（），
bitmap.getHeight（）， Config.ARGB_8888）;
Canvas canvas = new Canvas（output）;

final int color = 0 xff424242;
final Paint paint = new Paint（）;
final Rect rect = new Rect（0， 0， bitmap.getWidth（）， bitmap.getHeight（））;
final RectF rectF = new RectF（rect）;
final float roundPx = 12;

paint.setAntiAlias（true）;
canvas.drawARGB（0， 0， 0， 0）;
paint.setColor（color）;
canvas.drawRoundRect（rectF， roundPx， roundPx， paint）;

paint.setXfermode（new PorterDuffXfermode（Mode.SRC_IN））;
canvas.drawBitmap（bitmap， rect， rect， paint）;
return output;
}