diff options
Diffstat (limited to 'nuttx/graphics/nxglib/nxglib_filltrapezoid.c')
| -rw-r--r-- | nuttx/graphics/nxglib/nxglib_filltrapezoid.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/nuttx/graphics/nxglib/nxglib_filltrapezoid.c b/nuttx/graphics/nxglib/nxglib_filltrapezoid.c index 35ded6139..b20b46570 100644 --- a/nuttx/graphics/nxglib/nxglib_filltrapezoid.c +++ b/nuttx/graphics/nxglib/nxglib_filltrapezoid.c @@ -117,6 +117,12 @@ void NXGL_FUNCNAME(nxgl_filltrapezoid,NXGLIB_SUFFIX)( x1 = trap->top.x1; x2 = trap->top.x2; + /* Calculate the number of rows to render */ + + y1 = trap->top.y; + y2 = trap->bot.y; + nrows = y2 - y1 + 1; + /* Calculate the slope of the left and right side of the trapezoid */ dx1dy = b16divi((trap->bot.x1 - x1), nrows); @@ -124,28 +130,31 @@ void NXGL_FUNCNAME(nxgl_filltrapezoid,NXGLIB_SUFFIX)( /* Perform vertical clipping */ - y1 = trap->top.y; if (y1 < bounds->pt1.y) { + /* Calculate the x values for the new top run */ + int dy = bounds->pt1.y - y1; x1 += dy * dx1dy; x2 += dy * dx2dy; + + /* Clip and re-calculate the number of rows to render */ + y1 = bounds->pt1.y; + nrows = y2 - y1 + 1; } - y2 = trap->bot.y; if (y2 > bounds->pt2.y) { - y2 = bounds->pt2.y; - } + /* Clip and re-calculate the number of rows to render */ - /* Then calculate the number of rows to render */ - - nrows = y2 - y1 + 1; + y2 = bounds->pt2.y; + nrows = y2 - y1 + 1; + } /* Get the address of the first byte on the first line */ - line = pinfo->fbmem + y1 * stride ; + line = pinfo->fbmem + y1 * stride ; /* Then fill the trapezoid line-by-line */ |