From 07599d0bc43d805b8bf9a6a21a0315ef9b2699f7 Mon Sep 17 00:00:00 2001
From: Vadim Lopatin <buggins@fromru.com>
Date: Fri, 11 Apr 2014 14:40:12 +0400
Subject: [PATCH] color transform

---
 src/dlangui/graphics/drawbuf.d | 41 ++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/src/dlangui/graphics/drawbuf.d b/src/dlangui/graphics/drawbuf.d
index 593ef533..0d5a0718 100644
--- a/src/dlangui/graphics/drawbuf.d
+++ b/src/dlangui/graphics/drawbuf.d
@@ -3,6 +3,9 @@ module dlangui.graphics.drawbuf;
 public import dlangui.core.types;
 import dlangui.core.logger;
 
+immutable uint COLOR_TRANSFORM_OFFSET_NONE = 0x80808080;
+immutable uint COLOR_TRANSFORM_MULTIPLY_NONE = 0x80808080;
+
 /// blend two RGB pixels using alpha
 uint blendARGB(uint dst, uint src, uint alpha) {
     uint dstalpha = dst >> 24;
@@ -28,6 +31,26 @@ ubyte rgbToGray(uint color) {
     return cast(uint)(((srcr + srcg + srcg + srcb) >> 2) & 0xFF);
 }
 
+uint transformComponent(int src, int addBefore, int multiply, int addAfter) {
+    int add1 = (cast(int)(addBefore << 1)) - 0x100;
+    int add2 = (cast(int)(addAfter << 1)) - 0x100;
+    int mul = cast(int)(multiply << 2);
+    int res = (((src + add1) * mul) >> 8) + add2;
+    if (res < 0)
+        res = 0;
+    else if (res > 255)
+        res = 255;
+    return cast(uint)res;
+}
+
+uint transformRGBA(uint src, uint addBefore, uint multiply, uint addAfter) {
+    uint a = transformComponent(src >> 24, addBefore >> 24, multiply >> 24, addAfter >> 24);
+    uint r = transformComponent((src >> 16) & 0xFF, (addBefore >> 16) & 0xFF, (multiply >> 16) & 0xFF, (addAfter >> 16) & 0xFF);
+    uint g = transformComponent((src >> 8) & 0xFF, (addBefore >> 8) & 0xFF, (multiply >> 8) & 0xFF, (addAfter >> 8) & 0xFF);
+    uint b = transformComponent(src & 0xFF, addBefore & 0xFF, multiply & 0xFF, addAfter & 0xFF);
+    return (a << 24) | (r << 16) | (g << 8) | b;
+}
+
 /// blend two RGB pixels using alpha
 ubyte blendGray(ubyte dst, ubyte src, uint alpha) {
     uint ialpha = 256 - alpha;
@@ -237,6 +260,12 @@ class DrawBuf : RefCountedObject {
     void drawImage(int x, int y, DrawBuf src) {
         drawFragment(x, y, src, Rect(0, 0, src.width, src.height));
     }
+
+    /// create drawbuf with copy of current buffer with changed colors (returns this if not supported)
+    DrawBuf transformColors(uint addBefore, uint multiply, uint addAfter) {
+        return this;
+    }
+
     void clear() {}
     ~this() { clear(); }
 }
@@ -677,6 +706,18 @@ class ColorDrawBuf : ColorDrawBufBase {
         for (int i = 0; i < len; i++)
             p[i] = color;
     }
+    override DrawBuf transformColors(uint addBefore, uint multiply, uint addAfter) {
+        if (addBefore == COLOR_TRANSFORM_OFFSET_NONE && addAfter == COLOR_TRANSFORM_OFFSET_NONE && multiply == COLOR_TRANSFORM_MULTIPLY_NONE)
+            return this;
+        ColorDrawBuf res = new ColorDrawBuf(_dx, _dy);
+        for (int y = 0; y < _dy; y++) {
+            uint * srcline = scanLine(y);
+            uint * dstline = res.scanLine(y);
+            for (int x = 0; x < _dx; x++)
+                dstline[x] = transformRGBA(srcline[x], addBefore, multiply, addAfter);
+        }
+        return res;
+    }
 }