Factor out, simplify and document clipping.

[bertos.git] / gfx / bitmap.c

diff --git a/gfx/bitmap.c b/gfx/bitmap.c
index c9f1b83dce8ae2fb9b1bf722c37d45d3271f9bc2..d74c7735487c64a2957a8e9c3c83381045162357 100755 (executable)
--- a/gfx/bitmap.c
+++ b/gfx/bitmap.c
@@ -16,6 +16,12 @@
 
 /*#*
  *#* $Log$
+ *#* Revision 1.10  2006/05/27 17:21:15  bernie
+ *#* Factor out, simplify and document clipping.
+ *#*
+ *#* Revision 1.9  2006/05/25 23:35:40  bernie
+ *#* Cleanup.
+ *#*
  *#* Revision 1.8  2006/03/27 04:48:56  bernie
  *#* gfx_blitImage(): New function; gfx_blitRaster(): Fix clipping bug.
  *#*
@@ -95,6 +101,7 @@ void gfx_bitmapInit(Bitmap *bm, uint8_t *raster, coord_t w, coord_t h)
  * Clear the whole bitmap surface to the background color.
  *
  * \note This function does \b not update the current pen position.
+ * \note This function bypasses the current clipping area.
  */
 void gfx_bitmapClear(Bitmap *bm)
 {
@@ -118,6 +125,34 @@ void gfx_blit_P(Bitmap *bm, const pgm_uint8_t *raster)
 }
 #endif /* CPU_HARVARD */
 
+#if CONFIG_GFX_CLIPPING
+       /**
+        * Clip destination coordinates inside a clipping range.
+        *
+        * This macro helps a drawing operation to adjust its
+        * destination X and Y coordinates inside the destination
+        * clipping range.
+        *
+        * The source start coordinate is adjusted as well
+        * when destination start clipping occurs.
+        */
+       #define gfx_clip(dmin, dmax, smin, cmin, cmax) \
+               do { \
+                       if ((dmin) < (cmin)) \
+                       { \
+                               (smin) += (cmin) - (dmin); \
+                               (dmin) = (cmin); \
+                       } \
+                       (dmax) = MIN((dmax), (cmax)); \
+               } while(0)
+
+#else /* !CONFIG_GFX_CLIPPING */
+
+       #define gfx_clip(dmin, dmax, smin, cmin, cmax) do { } while (0)
+
+#endif /* !CONFIG_GFX_CLIPPING */
+
+
 /**
  * Copy a rectangular area of a bitmap on another bitmap.
  *
@@ -141,22 +176,19 @@ void gfx_blit(Bitmap *dst, const Rect *rect, const Bitmap *src, coord_t srcx, co
        coord_t dx, dy, sx, sy;
 
        /*
-        * Clip coordinates inside dst->cr and src->width/height.
+        * Pre-clip coordinates inside src->width/height.
         */
        dxmin = rect->xmin;
-       if (dxmin < dst->cr.xmin)
-       {
-               srcx += dst->cr.xmin - dxmin;
-               dxmin = dst->cr.xmin;
-       }
        dymin = rect->ymin;
-       if (dymin < dst->cr.ymin)
-       {
-               srcy += dst->cr.ymin - dymin;
-               dymin = dst->cr.ymin;
-       }
-       dxmax = MIN(MIN(rect->xmax, rect->xmin + src->width), dst->cr.xmax);
-       dymax = MIN(MIN(rect->ymax, rect->ymin + src->height), dst->cr.ymax);
+       dxmax = MIN(rect->xmax, rect->xmin + src->width);
+       dymax = MIN(rect->ymax, rect->ymin + src->height);
+
+       /* Perform regular clipping */
+       gfx_clip(dxmin, dxmax, srcx, dst->cr.xmin, dst->cr.xmax);
+       gfx_clip(dymin, dymax, srcy, dst->cr.ymin, dst->cr.ymax);
+
+       //kprintf("dxmin=%d, sxmin=%d, dxmax=%d; ", dxmin, sxmin, dxmax);
+       //kprintf("dymin=%d, symin=%d, dymax=%d\n", dymin, symin, dymax);
 
        /* TODO: make it not as dog slow as this */
        for (dx = dxmin, sx = srcx; dx < dxmax; ++dx, ++sx)
@@ -164,10 +196,11 @@ void gfx_blit(Bitmap *dst, const Rect *rect, const Bitmap *src, coord_t srcx, co
                        BM_DRAWPIXEL(dst, dx, dy, BM_READPIXEL(src, sx, sy));
 }
 
-
 /**
  * Blit a raster to a Bitmap.
  *
+ * \todo Merge this function into gfx_blit()
+ *
  * \see gfx_blit()
  */
 void gfx_blitRaster(Bitmap *dst, coord_t dxmin, coord_t dymin,
@@ -177,21 +210,9 @@ void gfx_blitRaster(Bitmap *dst, coord_t dxmin, coord_t dymin,
        coord_t sxmin = 0, symin = 0;
        coord_t dx, dy, sx, sy;
 
-       /*
-        * Clip coordinates inside dst->cr.
-        */
-       if (dxmin < dst->cr.xmin)
-       {
-               sxmin += dst->cr.xmin - dxmin;
-               dxmin = dst->cr.xmin;
-       }
-       if (dymin < dst->cr.ymin)
-       {
-               symin += dst->cr.ymin - dymin;
-               dymin = dst->cr.ymin;
-       }
-       dxmax = MIN(dxmax, dst->cr.xmax);
-       dymax = MIN(dymax, dst->cr.ymax);
+       /* Perform regular clipping */
+       gfx_clip(dxmin, dxmax, sxmin, dst->cr.xmin, dst->cr.xmax);
+       gfx_clip(dymin, dymax, symin, dst->cr.ymin, dst->cr.ymax);
 
        //kprintf("dxmin=%d, sxmin=%d, dxmax=%d; ", dxmin, sxmin, dxmax);
        //kprintf("dymin=%d, symin=%d, dymax=%d\n", dymin, symin, dymax);
@@ -216,13 +237,15 @@ void gfx_blitImage(Bitmap *dst, coord_t dxmin, coord_t dymin, const Image *image
 }
 
 
-/*!
+#if CONFIG_GFX_CLIPPING
+
+/**
  * Set the bitmap clipping rectangle to the specified coordinates.
  *
  * All drawing performed on the bitmap will be clipped inside this
  * rectangle.
  *
- * \note Following the convention used in all other operations, the
+ * \note Following the convention used for all other operations, the
  *       top-left pixels of the rectangle are included, while the
  *       bottom-right pixels are considered outside the clipping region.
  */
@@ -240,8 +263,9 @@ void gfx_setClipRect(Bitmap *bm, coord_t minx, coord_t miny, coord_t maxx, coord
        bm->cr.xmax = maxx;
        bm->cr.ymax = maxy;
 
-/*     kprintf("cr.xmin = %d, cr.ymin = %d, cr.xmax = %d, cr.ymax = %d\n",
-               bm->cr.xMin, bm->cr.ymin, bm->cr.xmax, bm->cr.ymax);
-*/
+//     kprintf("cr.xmin = %d, cr.ymin = %d, cr.xmax = %d, cr.ymax = %d\n",
+//             bm->cr.xMin, bm->cr.ymin, bm->cr.xmax, bm->cr.ymax);
 }
 
+#endif /* CONFIG_GFX_CLIPPING */
+