Drawable与 Bitmap 转换总结

程序员Android

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 ·

2020-10-25 16:46

和你一起终身学习,这里是程序员Android

经典好文推荐,通过阅读本文,您将收获以下知识点:

  1. 从资源中获取Bitmap

  2. Bitmap ----> byte[]

  3. byte[] ----> Bitmap

  4. Bitmap 缩放方法

  5. Drawable ----> Bitmap

  6. 圆角图片

  7. 获取带倒影的图片

  8. bitmap ----> Drawable

  9. drawable缩放 ,先转 bitmap 后缩放

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 SetRoundCornerBitmap(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

drawable缩放 ,先转bitmap,调用5中的方法 后缩放。

    // 9. drawable进行缩放 ---> bitmap 然后比对bitmap进行缩放
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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