Drawable 使用方法详解请看上篇文章.
- 从资源中获取Bitmap
- Bitmap ----> byte[]
- byte[] ----> Bitmap
- Bitmap 缩放方法
- Drawable ----> Bitmap
- 圆角图片
- 获取带倒影的图片
- bitmap ----> Drawable
- drawable缩放 ，先转 bitmap 后缩放
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1. 从资源中获取Bitmap
// 1.从资源中获取Bitmap
public void UseBitmap(Context context, ImageView imageView, int drawableId) {
Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(),
drawableId);
imageView.setImageBitmap(bitmap);
}
2. Bitmap ----> byte[]
// 2.Bitmap ---> byte[]
public byte[] BitmapToBytes(Bitmap bitmap) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
return baos.toByteArray();
}
3. byte[] ----> Bitmap
// 3.byte[] ---->bitmap
public Bitmap BytesToBitmap(byte[] b) {
if (b.length != 0) {
return BitmapFactory.decodeByteArray(b, 0, b.length);
} else {
return null;
}
}
4. Bitmap 缩放方法
// 4.Bitmap 缩放方法
public static Bitmap zoomBitmap(Bitmap bitmap, int width, int heigh) {
int w = bitmap.getWidth();
int h = bitmap.getHeight();
Matrix matrix = new Matrix();
float scalewidth = (float) width / w;
float scaleheigh = (float) heigh / h;
matrix.postScale(scalewidth, scaleheigh);
Bitmap newBmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);
return newBmp;
}
5. Drawable ----> Bitmap
// 5. Drawable----> Bitmap
public static Bitmap drawableToBitmap(Drawable drawable) {
// 获取 drawable 长宽
int width = drawable.getIntrinsicWidth();
int heigh = drawable.getIntrinsicHeight();
drawable.setBounds(0, 0, width, heigh);
// 获取drawable的颜色格式
Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
: Bitmap.Config.RGB_565;
// 创建bitmap
Bitmap bitmap = Bitmap.createBitmap(width, heigh, config);
// 创建bitmap画布
Canvas canvas = new Canvas(bitmap);
// 将drawable 内容画到画布中
drawable.draw(canvas);
return bitmap;
}
6. 圆角图片
-实现效果如下：
圆角图片
- 实现代码如下：
// 6.圆角图片
public static Bitmap getRoundCornerBitmap(Bitmap bitmap, float roundPx) {
int width = bitmap.getWidth();
int heigh = bitmap.getHeight();
// 创建输出bitmap对象
Bitmap outmap = Bitmap.createBitmap(width, heigh,
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(outmap);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, width, heigh);
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(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return outmap;
}
7. 获取带倒影的图片
- 实现效果如下：
带倒影的圆角图片
- 实现代码如下：
// 7.获取带倒影的图片
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),
Bitmap.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, Shader.TileMode.CLAMP);
paint.setShader(shader);
// Set the Transfer mode to be porter duff and destination in
paint.setXfermode(new PorterDuffXfermode(PorterDuff.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 ----> Drawable
// 8. bitmap ---Drawable
public static Drawable bitmapToDrawable(Bitmap bitmap, Context context) {
BitmapDrawable drawbale = new BitmapDrawable(context.getResources(),
bitmap);
return drawbale;
}
9. drawable缩放 ，先转 bitmap 后缩放
// 9. drawable缩放 ，先转 bitmap 后缩放
public static Drawable zoomDrawable(Drawable drawable, int w, int h) {
int width = drawable.getIntrinsicWidth();
int height = drawable.getIntrinsicHeight();
// 调用5 中 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);
}
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微信公众号：ProgramAndroid
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