1 files changed, 56 insertions, 38 deletions

diff --git a/src/gui/text/qfontengine_ft.cpp b/src/gui/text/qfontengine_ft.cpp
index 0d28785aa1..8dfabd48ad 100644
--- a/src/gui/text/qfontengine_ft.cpp
+++ b/src/gui/text/qfontengine_ft.cpp
@@ -534,69 +534,87 @@ QFontEngineFT::Glyph::~Glyph()
     delete [] data;
 }
 
-static const uint subpixel_filter[3][3] = {
-    { 180, 60, 16 },
-    { 38, 180, 38 },
-    { 16, 60, 180 }
+struct LcdFilterDummy
+{
+    static inline void filterPixel(uchar &, uchar &, uchar &)
+    {}
 };
 
-static inline uint filterPixel(uint red, uint green, uint blue, bool legacyFilter)
+struct LcdFilterLegacy
 {
-    uint res;
-    if (legacyFilter) {
-        uint high = (red*subpixel_filter[0][0] + green*subpixel_filter[0][1] + blue*subpixel_filter[0][2]) >> 8;
-        uint mid = (red*subpixel_filter[1][0] + green*subpixel_filter[1][1] + blue*subpixel_filter[1][2]) >> 8;
-        uint low = (red*subpixel_filter[2][0] + green*subpixel_filter[2][1] + blue*subpixel_filter[2][2]) >> 8;
-        res = (mid << 24) + (high << 16) + (mid << 8) + low;
-    } else {
-        uint alpha = green;
-        res = (alpha << 24) + (red << 16) + (green << 8) + blue;
+    static inline void filterPixel(uchar &red, uchar &green, uchar &blue)
+    {
+        uint r = red, g = green, b = blue;
+        // intra-pixel filter used by the legacy filter (adopted from _ft_lcd_filter_legacy)
+        red   = (r * uint(65538 * 9/13) + g * uint(65538 * 1/6) + b * uint(65538 * 1/13)) / 65536;
+        green = (r * uint(65538 * 3/13) + g * uint(65538 * 4/6) + b * uint(65538 * 3/13)) / 65536;
+        blue  = (r * uint(65538 * 1/13) + g * uint(65538 * 1/6) + b * uint(65538 * 9/13)) / 65536;
     }
-    return res;
-}
+};
 
-static void convertRGBToARGB(const uchar *src, uint *dst, int width, int height, int src_pitch, bool bgr, bool legacyFilter)
+template <typename LcdFilter>
+static void convertRGBToARGB_helper(const uchar *src, uint *dst, int width, int height, int src_pitch, bool bgr)
 {
-    int h = height;
     const int offs = bgr ? -1 : 1;
     const int w = width * 3;
-    while (h--) {
+    while (height--) {
         uint *dd = dst;
         for (int x = 0; x < w; x += 3) {
-            uint red = src[x+1-offs];
-            uint green = src[x+1];
-            uint blue = src[x+1+offs];
-            *dd = filterPixel(red, green, blue, legacyFilter);
-            ++dd;
+            uchar red = src[x + 1 - offs];
+            uchar green = src[x + 1];
+            uchar blue = src[x + 1 + offs];
+            LcdFilter::filterPixel(red, green, blue);
+            // alpha = green
+            *dd++ = (green << 24) | (red << 16) | (green << 8) | blue;
         }
         dst += width;
         src += src_pitch;
     }
 }
 
-static void convertRGBToARGB_V(const uchar *src, uint *dst, int width, int height, int src_pitch, bool bgr, bool legacyFilter)
+static inline void convertRGBToARGB(const uchar *src, uint *dst, int width, int height, int src_pitch, bool bgr, bool legacyFilter)
+{
+    if (!legacyFilter)
+        convertRGBToARGB_helper<LcdFilterDummy>(src, dst, width, height, src_pitch, bgr);
+    else
+        convertRGBToARGB_helper<LcdFilterLegacy>(src, dst, width, height, src_pitch, bgr);
+}
+
+template <typename LcdFilter>
+static void convertRGBToARGB_V_helper(const uchar *src, uint *dst, int width, int height, int src_pitch, bool bgr)
 {
-    int h = height;
     const int offs = bgr ? -src_pitch : src_pitch;
-    while (h--) {
+    while (height--) {
         for (int x = 0; x < width; x++) {
-            uint red = src[x+src_pitch-offs];
-            uint green = src[x+src_pitch];
-            uint blue = src[x+src_pitch+offs];
-            dst[x] = filterPixel(red, green, blue, legacyFilter);
+            uchar red = src[x + src_pitch - offs];
+            uchar green = src[x + src_pitch];
+            uchar blue = src[x + src_pitch + offs];
+            LcdFilter::filterPixel(red, green, blue);
+            // alpha = green
+            *dst++ = (green << 24) | (red << 16) | (green << 8) | blue;
         }
-        dst += width;
         src += 3*src_pitch;
     }
 }
 
-static void convertGRAYToARGB(const uchar *src, uint *dst, int width, int height, int src_pitch) {
-    for (int y = 0; y < height; ++y) {
-        int readpos =  (y * src_pitch);
-        int writepos = (y * width);
-        for (int x = 0; x < width; ++x) {
-            dst[writepos + x] = (0xFF << 24) + (src[readpos + x] << 16) + (src[readpos + x] << 8) + src[readpos + x];
+static inline void convertRGBToARGB_V(const uchar *src, uint *dst, int width, int height, int src_pitch, bool bgr, bool legacyFilter)
+{
+    if (!legacyFilter)
+        convertRGBToARGB_V_helper<LcdFilterDummy>(src, dst, width, height, src_pitch, bgr);
+    else
+        convertRGBToARGB_V_helper<LcdFilterLegacy>(src, dst, width, height, src_pitch, bgr);
+}
+
+static inline void convertGRAYToARGB(const uchar *src, uint *dst, int width, int height, int src_pitch)
+{
+    while (height--) {
+        const uchar *p = src;
+        const uchar * const e = p + width;
+        while (p < e) {
+            uchar gray = *p++;
+            *dst++ = (0xFF << 24) | (gray << 16) | (gray << 8) | gray;
         }
+        src += src_pitch;
     }
 }