diff --git a/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp b/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp
index 0347ad7..f740962 100644
--- a/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp
+++ b/ESP32-HUB75-MatrixPanel-I2S-DMA.cpp
@@ -768,8 +768,9 @@ uint8_t MatrixPanel_I2S_DMA::setLatBlanking(uint8_t pulses){
 void MatrixPanel_I2S_DMA::hlineDMA(int16_t x_coord, int16_t y_coord, int16_t l, uint8_t red, uint8_t green, uint8_t blue){
   if ( !initialized )
     return;
-
-  if ( x_coord < 0 || y_coord < 0 || l < 1 || x_coord >= PIXELS_PER_ROW || y_coord >= m_cfg.mx_height)
+	
+ // AdaFruit_GFX x and y co-ords start at 0 and go to width-1 or height-1 (i.e. 0-63, 0-31 for a 64x32 panel)
+  if ( x_coord < 0 || y_coord < 0 || l < 1 || x_coord > PIXELS_PER_ROW || y_coord > m_cfg.mx_height)
     return;
 
   if (x_coord+l > PIXELS_PER_ROW)
@@ -842,8 +843,9 @@ void MatrixPanel_I2S_DMA::hlineDMA(int16_t x_coord, int16_t y_coord, int16_t l,
 void MatrixPanel_I2S_DMA::vlineDMA(int16_t x_coord, int16_t y_coord, int16_t l, uint8_t red, uint8_t green, uint8_t blue){
   if ( !initialized )
     return;
-
-  if ( x_coord < 0 || y_coord < 0 || l < 1 || x_coord >= PIXELS_PER_ROW || y_coord >= m_cfg.mx_height)
+	
+  // AdaFruit_GFX x and y co-ords start at 0 and go to width-1 or height-1 (i.e. 0-63, 0-31 for a 64x32 panel)
+  if ( x_coord < 0 || y_coord < 0 || l < 1 || x_coord > PIXELS_PER_ROW || y_coord > m_cfg.mx_height) 
     return;
 
   if (y_coord + l > m_cfg.mx_height)
@@ -930,4 +932,4 @@ void MatrixPanel_I2S_DMA::fillRectDMA(int16_t x, int16_t y, int16_t w, int16_t h
   }
 }
 
-#endif  // NO_FAST_FUNCTIONS
\ No newline at end of file
+#endif  // NO_FAST_FUNCTIONS