Vincent Povirk : gdiplus: Account for blend factors and positions in line gradients.
Alexandre Julliard
julliard at winehq.org
Mon May 4 09:06:37 CDT 2009
Module: wine
Branch: master
Commit: a6161307cfd532b35b599078f78a97b4098220da
URL: http://source.winehq.org/git/wine.git/?a=commit;h=a6161307cfd532b35b599078f78a97b4098220da
Author: Vincent Povirk <vincent at codeweavers.com>
Date: Fri May 1 14:26:50 2009 -0500
gdiplus: Account for blend factors and positions in line gradients.
---
dlls/gdiplus/graphics.c | 36 ++++++++++++++++++++++++++++++++----
1 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/dlls/gdiplus/graphics.c b/dlls/gdiplus/graphics.c
index 36cb324..b467dc7 100644
--- a/dlls/gdiplus/graphics.c
+++ b/dlls/gdiplus/graphics.c
@@ -172,15 +172,43 @@ static void transform_and_round_points(GpGraphics *graphics, POINT *pti,
}
}
-static ARGB blend_colors(ARGB start, ARGB end, int current, int total)
+static ARGB blend_colors(ARGB start, ARGB end, REAL position)
{
ARGB result=0;
ARGB i;
for (i=0xff; i<=0xff0000; i = i << 8)
- result |= (((start&i)*(total - current)+(end&i)*(current))/total)&i;
+ result |= (int)((start&i)*(1.0f - position)+(end&i)*(position))&i;
return result;
}
+static ARGB blend_line_gradient(GpLineGradient* brush, REAL position)
+{
+ REAL blendfac;
+
+ if (brush->blendcount == 1)
+ blendfac = position;
+ else
+ {
+ int i=1;
+ REAL left_blendpos, left_blendfac, right_blendpos, right_blendfac;
+ REAL range;
+
+ /* locate the blend positions surrounding this position */
+ while (position > brush->blendpos[i])
+ i++;
+
+ /* interpolate between the blend positions */
+ left_blendpos = brush->blendpos[i-1];
+ left_blendfac = brush->blendfac[i-1];
+ right_blendpos = brush->blendpos[i];
+ right_blendfac = brush->blendfac[i];
+ range = right_blendpos - left_blendpos;
+ blendfac = (left_blendfac * (right_blendpos - position) +
+ right_blendfac * (position - left_blendpos)) / range;
+ }
+ return blend_colors(brush->startcolor, brush->endcolor, blendfac);
+}
+
static void brush_fill_path(GpGraphics *graphics, GpBrush* brush)
{
switch (brush->bt)
@@ -240,7 +268,7 @@ static void brush_fill_path(GpGraphics *graphics, GpBrush* brush)
for (i=1; i<num_steps; i++)
{
- ARGB argb = blend_colors(line->startcolor, line->endcolor, i, num_steps);
+ ARGB argb = blend_line_gradient(line, i/(REAL)num_steps);
int ofs = width * i / num_steps;
col = ARGB2COLORREF(argb);
hbrush = CreateSolidBrush(col);
@@ -296,7 +324,7 @@ static void brush_fill_path(GpGraphics *graphics, GpBrush* brush)
for (i=1; i<num_steps; i++)
{
- ARGB argb = blend_colors(line->startcolor, line->endcolor, i, num_steps);
+ ARGB argb = blend_line_gradient(line, i/(REAL)num_steps);
int ofs = height * i / num_steps;
col = ARGB2COLORREF(argb);
hbrush = CreateSolidBrush(col);
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