一、相关概念
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
二、Bitmap
1、从资源中获取Bitmap
Resources res = getResources();
Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.icon);
Resources res = getResources();Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.icon);
2、Bitmap → byte[]
public byte[] Bitmap2Bytes(Bitmap bm) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
return baos.toByteArray();
}
public byte[] Bitmap2Bytes(Bitmap bm) {ByteArrayOutputStream baos = new ByteArrayOutputStream();bm.compress(Bitmap.CompressFormat.PNG, 100, baos);return baos.toByteArray();}
3、byte[] → Bitmap
public Bitmap Bytes2Bimap(byte[] b) {
if (b.length != 0) {
return BitmapFactory.decodeByteArray(b, 0, b.length);
} else {
return null;
}
}
public Bitmap Bytes2Bimap(byte[] b) {if (b.length != 0) {return BitmapFactory.decodeByteArray(b, 0, b.length);} else {return null;}}
4、Bitmap缩放
public static Bitmap zoomBitmap(Bitmap bitmap, int width, int height) {int w = bitmap.getWidth();int h = bitmap.getHeight();Matrix matrix = new Matrix();float scaleWidth = ((float) width / w);float scaleHeight = ((float) height / h);matrix.postScale(scaleWidth, scaleHeight);Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);return newbmp;}
5、将Drawable转化为Bitmap
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;
}
public static Bitmap drawableToBitmap(Drawable drawable) {// 取 drawable 的长宽int w = drawable.getIntrinsicWidth();int h = drawable.getIntrinsicHeight();// 取 drawable 的颜色格式Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888: Bitmap.Config.RGB_565;// 建立对应 bitmapBitmap bitmap = Bitmap.createBitmap(w, h, config);// 建立对应 bitmap 的画布Canvas canvas = new Canvas(bitmap);drawable.setBounds(0, 0, w, h);// 把 drawable 内容画到画布中drawable.draw(canvas);return bitmap;}
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;
- }
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
Java代码
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;
}
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 inpaint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));// Draw a rectangle using the paint with our linear gradientcanvas.drawRect(0, h, w, bitmapWithReflection.getHeight()+ reflectionGap, paint);return bitmapWithReflection;}
三、Drawable
1、Bitmap转换成Drawable
Java代码:
Bitmap bm=xxx; //xxx根据你的情况获取
BitmapDrawable bd= new BitmapDrawable(getResource(), bm);
因为BtimapDrawable是Drawable的子类,最终直接使用bd对象即可。
Bitmap bm=xxx; //xxx根据你的情况获取BitmapDrawable bd= new BitmapDrawable(getResource(), bm); 因为BtimapDrawable是Drawable的子类,最终直接使用bd对象即可。
2、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);
}
原文链接:http://dyh7077063.iteye.com/blog/970672
/**
* 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 ;
}
}