1 files changed, 42 insertions, 18 deletions

diff --git a/nuttx/graphics/nxglib/nxglib_filltrapezoid.c b/nuttx/graphics/nxglib/nxglib_filltrapezoid.c
index 2343a4680..a4ea25e51 100644
--- a/nuttx/graphics/nxglib/nxglib_filltrapezoid.c
+++ b/nuttx/graphics/nxglib/nxglib_filltrapezoid.c
@@ -79,20 +79,24 @@
  *
  * Descripton:
  *   Fill a trapezoidal region in the framebuffer memory with a fixed color.
- *   This is useful for drawing complex shape -- (most) complex shapes can be
- *   broken into a set of trapezoids.
+ *   Clip the trapezoid to lie within a boundng box.  This is useful for
+ *   drawing complex shapes that can be broken into a set of trapezoids.
  *
  ****************************************************************************/
 
-void NXGL_FUNCNAME(nxglib_filltrapezoid,NXGLIB_SUFFIX)
-(FAR struct fb_videoinfo_s *vinfo, FAR struct fb_planeinfo_s *pinfo,
- FAR const struct nxgl_trapezoid_s *trap, nxgl_mxpixel_t color)
+void NXGL_FUNCNAME(nxgl_filltrapezoid,NXGLIB_SUFFIX)(
+  FAR struct fb_planeinfo_s *pinfo,
+  FAR const struct nxgl_trapezoid_s *trap,
+  FAR const struct nxgl_rect_s *bounds,
+  nxgl_mxpixel_t color)
 {
   unsigned int stride;
   ubyte *line;
   int nrows;
   b16_t x1;
   b16_t x2;
+  nxgl_coord_t y1;
+  nxgl_coord_t y2;
   b16_t dx1dy;
   b16_t dx2dy;
 
@@ -102,18 +106,38 @@ void NXGL_FUNCNAME(nxglib_filltrapezoid,NXGLIB_SUFFIX)
 
   /* Get the top run position and the number of rows to draw */
 
-  x1     = trap->top.x1;
-  x2     = trap->top.x2;
-  nrows  = trap->bot.y - trap->top.y + 1;
+  x1 = trap->top.x1;
+  x2 = trap->top.x2;
 
-  /* Get the address of the first byte on the first line */
+  /* Calculate the slope of the left and right side of the trapezoid */
 
-  line   = pinfo->fbmem + trap->top.y * stride ;
+  dx1dy = b16divi((trap->bot.x1 - x1), nrows);
+  dx2dy = b16divi((trap->bot.x2 - x2), nrows);
 
-  /* Calculate the slope of the left and right side of the trapezoid */
+  /* Perform vertical clipping */
+
+  y1 = trap->top.y;
+  if (y1 < bounds->pt1.y)
+    {
+      int dy = bounds->pt1.y - y1;
+      x1    += dy * dx1dy;
+      x2    += dy * dx2dy;
+      y1     = bounds->pt1.y;
+    }
+
+  y2 = trap->bot.y;
+  if (y2 > bounds->pt2.y)
+    {
+      y2 = bounds->pt2.y;
+    }
+
+  /* Then calculate the number of rows to render */
+
+  nrows  = y2 - y1 + 1;
+
+  /* Get the address of the first byte on the first line */
 
-  dx1dy  = b16divi((trap->bot.x1 - x1), nrows);
-  dx2dy  = b16divi((trap->bot.x2 - x2), nrows);
+  line   = pinfo->fbmem + y1 * stride ;
 
   /* Then fill the trapezoid line-by-line */
 
@@ -140,17 +164,17 @@ void NXGL_FUNCNAME(nxglib_filltrapezoid,NXGLIB_SUFFIX)
        * always draw at least one pixel.
        */
 
-      if (x1 > x2 || ix2 < 0 || ix1 > vinfo->yres)
+      if (x1 > x2 || ix2 < bounds->pt1.x || ix1 > bounds->pt2.x)
         {
-          /* Get a clipped copies of the startingand ending X positions.  This
+          /* Get a clipped copies of the starting and ending X positions.  This
            * clipped truncates "down" and gives the quantized pixel holding the
            * fractional X position
            */
 
-          ix1 = ngl_clipl(ix1, 0);
-          ix2 = ngl_clipr(ix2, vinfo->yres);
+          ix1 = ngl_clipl(ix1, bounds->pt1.x);
+          ix2 = ngl_clipr(ix2, bounds->pt2.x);
 
-          /* Then draw the run from (line + clipx1) to (line + clipx2) */
+          /* Then draw the run from (line + ix1) to (line + ix2) */
 
           NXGL_MEMSET(line + NXGL_SCALEX(ix1), (NXGL_PIXEL_T)color, ix2 - ix1 + 1);
         }