[Swingme-svn] SF.net SVN: swingme:[2973] iOSME/src/javax/microedition/lcdui/Image.java

[<yu...@us...>]

Revision: 2973
          http://sourceforge.net/p/swingme/code/2973
Author:   yuranet
Date:     2025-12-13 14:40:04 +0000 (Sat, 13 Dec 2025)
Log Message:
-----------
unpremultiply also done

Modified Paths:
--------------
    iOSME/src/javax/microedition/lcdui/Image.java

Modified: iOSME/src/javax/microedition/lcdui/Image.java
===================================================================
--- iOSME/src/javax/microedition/lcdui/Image.java	2025-12-13 13:56:43 UTC (rev 2972)
+++ iOSME/src/javax/microedition/lcdui/Image.java	2025-12-13 14:40:04 UTC (rev 2973)
@@ -297,7 +297,7 @@
         return context;
     }
 
-    public static final Image createRGBImage(int[] rgb, int width, int height, boolean processAlpha) {
+    public static Image createRGBImage(int[] rgb, int width, int height, boolean processAlpha) {
         // TODO not optimum as we first create white image
         Image img = createImage(width, height);
         img.setRGB(rgb, 0, width, width, height, processAlpha);
@@ -491,6 +491,15 @@
         for (int c = 0; c < height; c++) {
             intPtr.copyTo((y+c) * srcScanLenght + x, rgb, offset + c * distScanLength, width);
         }
+
+        int alphaMode = CoreGraphics.CGBitmapContextGetBitmapInfo(context) & CGBitmapInfo.AlphaInfoMask;
+        if (alphaMode == CGImageAlphaInfo.PremultipliedFirst || alphaMode == CGImageAlphaInfo.PremultipliedLast) {
+            for (int a = 0; a < height; a++) {
+                for (int b = 0; b < width; b++) {
+                    rgb[offset + a * distScanLength + b] = unpremultiply(rgb[offset + a * distScanLength + b]);
+                }
+            }
+        }
     }
 
     public void setRGB(int[] rgbData, int offset, int srcScanLength, int width, int height, boolean processAlpha) {
@@ -524,6 +533,10 @@
         }
     }
 
+    /**
+     * TODO maybe we can use a system apple function to do this
+     * @see apple.accelerate.c.Accelerate#vImagePremultiplyData_ARGB8888(apple.accelerate.struct.vImage_Buffer, apple.accelerate.struct.vImage_Buffer, int)
+     */
     private static int premultiplyAlpha(int argb) {
         int a = argb >>> 24;
         if (a == 255) return argb;
@@ -537,11 +550,35 @@
         return (a << 24) | (r << 16) | (g << 8) | b;
     }
 
+    /**
+     * TODO maybe we can use a system apple function to do this
+     * @see apple.accelerate.c.Accelerate#vImageUnpremultiplyData_ARGB8888(apple.accelerate.struct.vImage_Buffer, apple.accelerate.struct.vImage_Buffer, int)
+     */
+    public static int unpremultiply(int argb) {
+        int a = argb >>> 24;          // alpha 0..255
+        if (a == 0 || a == 255) return argb; // fully transparent or opaque, no change needed
+
+        int r = (argb >> 16) & 0xFF;
+        int g = (argb >> 8)  & 0xFF;
+        int b = argb & 0xFF;
+
+        // reverse premultiply with rounding
+        r = (r * 255 + a / 2) / a;
+        g = (g * 255 + a / 2) / a;
+        b = (b * 255 + a / 2) / a;
+
+        return (a << 24) | (r << 16) | (g << 8) | b;
+    }
+
     public void setRGB(int x, int y, int color) {
         Graphics g = getGraphics();
+        CGContextRef context = g.getContext();
         int srcScanLenght = getIntsPerRow();
-        IntPtr intPtr = CoreGraphics.CGBitmapContextGetData(g.getContext()).getIntPtr();
-        intPtr.setValue(y * srcScanLenght + x, color);
+        int alphaMode = CoreGraphics.CGBitmapContextGetBitmapInfo(context) & CGBitmapInfo.AlphaInfoMask;
+        IntPtr intPtr = CoreGraphics.CGBitmapContextGetData(context).getIntPtr();
+        intPtr.setValue(y * srcScanLenght + x,
+                alphaMode == CGImageAlphaInfo.PremultipliedFirst || alphaMode == CGImageAlphaInfo.PremultipliedLast ?
+                premultiplyAlpha(color) : color);
     }
 
     public static void filter(Image source, Image bm, ColorMatrix cm) {

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