Speed up midpoint lines starting far outside the device bounds.

Reviewed-By: Samuel

1 files changed, 14 insertions, 0 deletions

diff --git a/src/gui/painting/qpaintengine_raster.cpp b/src/gui/painting/qpaintengine_raster.cpp
index 8b83f02..547818c 100644
--- a/src/gui/painting/qpaintengine_raster.cpp
+++ b/src/gui/painting/qpaintengine_raster.cpp
@@ -5198,6 +5198,13 @@ static void drawLine_midpoint_i(int x1, int y1, int x2, int y2, ProcessSpans spa
             dy = -dy;
         }
 
+        int x_lower_limit = - 128;
+        if (x1 < x_lower_limit) {
+            int cy = dy * (x_lower_limit - x1) / dx + y1;
+            drawLine_midpoint_i(x_lower_limit, cy, x2, y2, span_func, data, style, devRect);
+            return;
+        }
+
         if (style == LineDrawNormal)
             --x2;
 
@@ -5335,6 +5342,13 @@ static void drawLine_midpoint_i(int x1, int y1, int x2, int y2, ProcessSpans spa
             dx = -dx;
         }
 
+        int y_lower_limit = - 128;
+        if (y1 < y_lower_limit) {
+            int cx = dx * (y_lower_limit - y1) / dy + x1;
+            drawLine_midpoint_i(cx, y_lower_limit, x2, y2, span_func, data, style, devRect);
+            return;
+        }
+
         if (style == LineDrawNormal)
             --y2;