How to crop a .png EncodedImage in BlackBerry while preserving transparency
I have a single .png image with several icons on it (with transpar开发者_JAVA百科ent areas) and would like to crop individual icons from it. In Java ME it was rather straight-forward, but in BlackBerry I haven't found an equivalent. The code here shows an example with a Bitmap, however doing so paints the transparent areas with white color:
public Bitmap cropImage(Bitmap image, int x, int y, int width, int height) {
Bitmap result = new Bitmap(width, height);
Graphics g = new Graphics(result);
g.drawBitmap(0, 0, width, height, image, x, y);
return result;
}
I need the same for an EncodedImage to keep the transparency, but Graphics
constructor accepts only a Bitmap
. Is there any other way to accomplish this? Thank you for any tips.
UPDATE:
Transparency can be preserved if you omit the intermediate Graphics object altogether, and set the ARGB data directly to the newly created Bitmap, like so:
public Bitmap cropImage(Bitmap image, int x, int y, int width, int height) {
Bitmap result = new Bitmap(width, height);
int[] argbData = new int[width * height];
image.getARGB(argbData, 0, width, x, y, width, height);
result.setARGB(argbData, 0, width, 0, 0, width, height);
return result;
}
Sorry I didn't try this code but it should give you the idea:
int[] argbData = new int[ width * height ];
image.getARGB( argbData,
0,
width
x,
y,
width,
height);
Bitmap result = new Bitmap(width, height);
Graphics g = new Graphics(result);
g.drawARGB(argbData , 0, width, 0, 0, width, height);
return result;
try to use
g.setGlobalAlpha(0);
before
g.drawBitmap(0, 0, width, height, image, x, y);
or you can use
drawARGB(int[] data, int offset, int scanLength, int x, int y, int width, int height)
which preserve the alpha in the destination image.
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