Avoid floating-point divisions in the Bresenham resize.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@4691 92316355-f0b4-4df1-b90c-862c8a59935f

pipi/resample/bresenham.c

@@ -37,6 +37,7 @@ pipi_image_t *pipi_resize(pipi_image_t *src, int w, int h)
     pipi_image_t *dst;
     pipi_pixels_t *srcp, *dstp;
     int x, y, x0, y0, sw, dw, sh, dh, remy;
+    float invswsh;
 
     srcp = pipi_get_pixels(src, PIPI_PIXELS_RGBA_F32);
     srcdata = (float *)srcp->pixels;
@@ -47,6 +48,7 @@ pipi_image_t *pipi_resize(pipi_image_t *src, int w, int h)
 
     sw = src->w; sh = src->h;
     dw = dst->w; dh = dst->h;
+    invswsh = 1.0f / (sw * sh);
 
     aline = malloc(4 * dw * sizeof(float));
     line = malloc(4 * dw * sizeof(float));
@@ -114,10 +116,10 @@ pipi_image_t *pipi_resize(pipi_image_t *src, int w, int h)
 
         for(x = 0; x < dw; x++)
         {
-            dstdata[(y * dw + x) * 4] = aline[4 * x] / (sw * sh);
-            dstdata[(y * dw + x) * 4 + 1] = aline[4 * x + 1] / (sw * sh);
-            dstdata[(y * dw + x) * 4 + 2] = aline[4 * x + 2] / (sw * sh);
-            dstdata[(y * dw + x) * 4 + 3] = aline[4 * x + 3] / (sw * sh);
+            dstdata[(y * dw + x) * 4] = aline[4 * x] * invswsh;
+            dstdata[(y * dw + x) * 4 + 1] = aline[4 * x + 1] * invswsh;
+            dstdata[(y * dw + x) * 4 + 2] = aline[4 * x + 2] * invswsh;
+            dstdata[(y * dw + x) * 4 + 3] = aline[4 * x + 3] * invswsh;
         }
     }