安卓中关于图片的类型
2015-10-27 10:49
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1、Drawable就是一个可画的对象,
其可能是一张位图(BitmapDrawable),
也可能是一个图形(ShapeDrawable),
还有可能是一个图层(LayerDrawable),我们根据画图的需求,创建相应的可画对象
2、Canvas画布,绘图的目的区域,用于绘图
3、Bitmap位图,用于图的处理
4、Matrix矩阵
6、获得圆角图片
7、获得带倒影的图片
8、Bitmap转换成Drawable
/**
* Drawable 转 bitmap
* @param drawable
* @return
*/
public static Bitmap drawable2Bitmap(Drawable drawable){
if(drawable instanceof BitmapDrawable){
return ((BitmapDrawable)drawable).getBitmap() ;
}else if(drawable instanceof NinePatchDrawable){
Bitmap bitmap = Bitmap
.createBitmap(
drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight(),
drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
: Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight());
drawable.draw(canvas);
return bitmap;
}else{
return null ;
}
}
“`
其可能是一张位图(BitmapDrawable),
也可能是一个图形(ShapeDrawable),
还有可能是一个图层(LayerDrawable),我们根据画图的需求,创建相应的可画对象
2、Canvas画布,绘图的目的区域,用于绘图
3、Bitmap位图,用于图的处理
4、Matrix矩阵
涉及到的操作:
6、获得圆角图片
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) { int w = bitmap.getWidth(); int h = bitmap.getHeight(); Bitmap output = Bitmap.createBitmap(w, h, Config.ARGB_8888); Canvas canvas = new Canvas(output); final int color = 0xff424242; final Paint paint = new Paint(); final Rect rect = new Rect(0, 0, w, h); final RectF rectF = new RectF(rect); 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; }
7、获得带倒影的图片
public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap) { final int reflectionGap = 4; int w = bitmap.getWidth(); int h = bitmap.getHeight(); Matrix matrix = new Matrix(); matrix.preScale(1, -1); Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, h / 2, w, h / 2, matrix, false); Bitmap bitmapWithReflection = Bitmap.createBitmap(w, (h + h / 2), Config.ARGB_8888); Canvas canvas = new Canvas(bitmapWithReflection); canvas.drawBitmap(bitmap, 0, 0, null); Paint deafalutPaint = new Paint(); canvas.drawRect(0, h, w, h + reflectionGap, deafalutPaint); canvas.drawBitmap(reflectionImage, 0, h + reflectionGap, null); Paint paint = new Paint(); LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0, bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP); paint.setShader(shader); // Set the Transfer mode to be porter duff and destination in paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN)); // Draw a rectangle using the paint with our linear gradient canvas.drawRect(0, h, w, bitmapWithReflection.getHeight() + reflectionGap, paint); return bitmapWithReflection; }
8、Bitmap转换成Drawable
Bitmap bm=xxx; //xxx根据你的情况获取 2.BitmapDrawable bd= new BitmapDrawable(getResource(), bm); 3.因为BtimapDrawable是Drawable的子类,最终直接使用bd对象即可。 `` 9、Drawable缩放
public static Drawable zoomDrawable(Drawable drawable, int w, int h) { int width = drawable.getIntrinsicWidth(); int height = drawable.getIntrinsicHeight(); // drawable转换成bitmap Bitmap oldbmp = drawableToBitmap(drawable); // 创建操作图片用的Matrix对象 Matrix matrix = new Matrix(); // 计算缩放比例 float sx = ((float) w / width); float sy = ((float) h / height); // 设置缩放比例 matrix.postScale(sx, sy); // 建立新的bitmap,其内容是对原bitmap的缩放后的图 Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height, matrix, true); return new BitmapDrawable(newbmp); }
10、drawable--》bitmap
/**
* Drawable 转 bitmap
* @param drawable
* @return
*/
public static Bitmap drawable2Bitmap(Drawable drawable){
if(drawable instanceof BitmapDrawable){
return ((BitmapDrawable)drawable).getBitmap() ;
}else if(drawable instanceof NinePatchDrawable){
Bitmap bitmap = Bitmap
.createBitmap(
drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight(),
drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
: Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight());
drawable.draw(canvas);
return bitmap;
}else{
return null ;
}
}
“`
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