Merge pull request #1049 from pimoroni/patch-pixel-span

Gadgetoid · web-flow · commit d014b289d670 · 2025-01-15T09:01:45.000Z
PicoGraphics: Fix overflow bug in p4 pixel span.
diff --git a/libraries/pico_graphics/pico_graphics_pen_p4.cpp b/libraries/pico_graphics/pico_graphics_pen_p4.cpp
@@ -70,6 +70,10 @@ namespace pimoroni {
     }
 
     void PicoGraphics_PenP4::set_pixel_span(const Point &p, uint l) {
+        // prevent a zero length span causing an overflow in 'l'
+        // and trying to write 2GB of pixels.
+        if (l == 0) {return;}
+
         auto i = (p.x + p.y * bounds.w);
 
         // pointer to byte in framebuffer that contains this pixel

Original file line number	Diff line number	Diff line change
`@@ -70,6 +70,10 @@ namespace pimoroni {`
`70`	`70`	`}`
`71`	`71`
`72`	`72`	`void PicoGraphics_PenP4::set_pixel_span(const Point &p, uint l) {`
	`73`	`+ // prevent a zero length span causing an overflow in 'l'`
	`74`	`+ // and trying to write 2GB of pixels.`
	`75`	`+ if (l == 0) {return;}`
	`76`	`+`
`73`	`77`	`auto i = (p.x + p.y * bounds.w);`
`74`	`78`
`75`	`79`	`// pointer to byte in framebuffer that contains this pixel`