From 6b4739aec90d0497a6c54bda65f94f7402c68a80 Mon Sep 17 00:00:00 2001
From: Christian Walther <cwalther@gmx.ch>
Date: Wed, 25 Jan 2012 22:16:19 +0100
Subject: [PATCH] Implement shadowed text rendering.

Intended to make KI text (player list and chat) better readable on light and patterned backgrounds. In this WIP, all text on GUI controls is rendered shadowed.
---
 Sources/Plasma/PubUtilLib/plGImage/plFont.cpp | 82 ++++++++++++++++++-
 Sources/Plasma/PubUtilLib/plGImage/plFont.h   |  7 ++
 2 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/Sources/Plasma/PubUtilLib/plGImage/plFont.cpp b/Sources/Plasma/PubUtilLib/plGImage/plFont.cpp
index 764c77f1..ffa5468f 100644
--- a/Sources/Plasma/PubUtilLib/plGImage/plFont.cpp
+++ b/Sources/Plasma/PubUtilLib/plGImage/plFont.cpp
@@ -335,7 +335,12 @@ void    plFont::IRenderString( plMipmap *mip, uint16_t x, uint16_t y, const wcha
             if( fRenderInfo.fFlags & kRenderIntoAlpha )
             {
                 if( fRenderInfo.fFlags & kRenderAlphaPremultiplied )
-                    fRenderInfo.fRenderFunc = &plFont::IRenderChar8To32AlphaPremultiplied;
+                {
+                    if (1)//( ( fRenderInfo.fColor & 0x00ffffff ) == 0x00ffffff ) //FIXME
+                        fRenderInfo.fRenderFunc = &plFont::IRenderChar8To32AlphaPremShadow;
+                    else
+                        fRenderInfo.fRenderFunc = &plFont::IRenderChar8To32AlphaPremultiplied;
+                }
                 else if( ( fRenderInfo.fColor & 0xff000000 ) != 0xff000000 )
                     fRenderInfo.fRenderFunc = &plFont::IRenderChar8To32Alpha;
                 else
@@ -1082,6 +1087,81 @@ void    plFont::IRenderChar8To32AlphaPremultiplied( const plFont::plCharacter &c
     }
 }
 
+void    plFont::IRenderChar8To32AlphaPremShadow( const plFont::plCharacter &c )
+{
+    uint32_t  *destPtr, *destBasePtr = (uint32_t *)( fRenderInfo.fDestPtr - c.fBaseline * fRenderInfo.fDestStride );
+    int16_t   x, y, thisHeight, xstart, thisWidth;
+    uint8_t   srcA, srcR, srcG, srcB;
+
+
+    // Unfortunately for some fonts, their right kern value actually is
+    // farther left than the right edge of the bitmap (think of overlapping
+    // script fonts). Ideally, we should store the actual width of each char's
+    // bitmap and use that here. However, it really shouldn't make too big of a
+    // difference, especially since the dest pixels that we end up overlapping
+    // should already be in the cache. If it does, time to upgrade the font
+    // format (again)
+    thisWidth = fWidth + 2;// + (int32_t)c.fRightKern;
+    if( thisWidth >= fRenderInfo.fMaxWidth )
+        thisWidth = fRenderInfo.fMaxWidth;
+
+    xstart = fRenderInfo.fClipRect.fX - fRenderInfo.fX;
+    if( xstart < -2 )
+        xstart = -2;
+
+    srcA = (uint8_t)(( fRenderInfo.fColor >> 24 ) & 0x000000ff);
+    srcR = (uint8_t)(( fRenderInfo.fColor >> 16 ) & 0x000000ff);
+    srcG = (uint8_t)(( fRenderInfo.fColor >> 8  ) & 0x000000ff);
+    srcB = (uint8_t)(( fRenderInfo.fColor       ) & 0x000000ff);
+
+    static const uint32_t kernel[5][5] = {
+        {1,  2,  2,  2, 1},
+        {1, 13, 13, 13, 1},
+        {1, 10, 10, 10, 1},
+        {1,  7,  7,  7, 1},
+        {1,  1,  1,  1, 1}
+    };
+
+    uint32_t clamp = 220 - ((2 * srcR + 4 * srcG + srcB) >> 4);
+
+    y = fRenderInfo.fClipRect.fY - fRenderInfo.fY + (int16_t)c.fBaseline;
+    if( y < -2 )
+        y = -2;
+    destBasePtr = (uint32_t *)( (uint8_t *)destBasePtr + y*fRenderInfo.fDestStride );
+
+    thisHeight = fRenderInfo.fMaxHeight + (int16_t)c.fBaseline;
+    if( thisHeight > (int16_t)c.fHeight + 2 )
+        thisHeight = (int16_t)c.fHeight + 2;
+
+    for( ; y < thisHeight; y++ )
+    {
+        destPtr = destBasePtr;
+        for( x = xstart; x < thisWidth; x++ )
+        {
+            uint32_t sa = 0;
+            for (int32_t i = -2; i <= 2; i++) {
+                for (int32_t j = -2; j <= 2; j++) {
+                    uint32_t m = kernel[j+2][i+2];
+                    if (m != 0)
+                        sa += m * IGetCharPixel(c, x+i, y+j);
+                }
+            }
+            sa = (sa * clamp) >> 13;
+            if (sa > clamp)
+                sa = clamp;
+            uint32_t a = IGetCharPixel(c, x, y);
+            if (srcA != 0xff)
+                a = (srcA * a + 127) / 255;
+            uint32_t ta = a + sa - ((a*sa + 127) / 255);
+            if (ta > (destPtr[ x ] >> 24))
+                destPtr[ x ] = ( ta << 24 ) | (((srcR * a + 127) / 255) << 16) |
+                                              (((srcG * a + 127) / 255) <<  8) |
+                                              (((srcB * a + 127) / 255) <<  0);
+        }
+        destBasePtr = (uint32_t *)( (uint8_t *)destBasePtr + fRenderInfo.fDestStride );
+    }
+}
+
 
 void    plFont::IRenderCharNull( const plCharacter &c )
 {
diff --git a/Sources/Plasma/PubUtilLib/plGImage/plFont.h b/Sources/Plasma/PubUtilLib/plGImage/plFont.h
index 20dae743..4123fa56 100644
--- a/Sources/Plasma/PubUtilLib/plGImage/plFont.h
+++ b/Sources/Plasma/PubUtilLib/plGImage/plFont.h
@@ -233,8 +233,15 @@ class plFont : public hsKeyedObject
         void    IRenderChar8To32Alpha( const plCharacter &c );
         void    IRenderChar8To32FullAlpha( const plCharacter &c );
         void    IRenderChar8To32AlphaPremultiplied( const plCharacter &c );
+        void    IRenderChar8To32AlphaPremShadow( const plCharacter &c );
         void    IRenderCharNull( const plCharacter &c );
 
+        uint32_t IGetCharPixel( const plCharacter &c, int32_t x, int32_t y )
+        {
+            // only for 8-bit characters
+            return (x < 0 || y < 0 || (uint32_t)x >= fWidth || (uint32_t)y >= c.fHeight) ? 0 : *(fBMapData + c.fBitmapOff + y*fWidth + x);
+        }
+
     public:
 
         plFont();