DV Display: Allow scrolling by single pixel in x coordinate

drivers/dv_display/dv_display.cpp

@@ -20,10 +20,10 @@ namespace pimoroni {
     display_height = display_height_;
     mode = mode_;
 
-    if (frame_width == 0) frame_width = display_width_;
+    if (frame_width_ == 0) frame_width = display_width_;
     else frame_width = frame_width_;
 
-    if (frame_height == 0) frame_height = display_height_;
+    if (frame_height_ == 0) frame_height = display_height_;
     else frame_height = frame_height_;
 
     bank = 0;
@@ -130,9 +130,6 @@ namespace pimoroni {
 
   void DVDisplay::set_display_offset(const Point& p) {
     int32_t offset = (int32_t)point_to_address(p) - (int32_t)point_to_address({0,0});
-    while (offset & 3) {
-      offset -= pixel_size();
-    }
     i2c->write_bytes(I2C_ADDR, I2C_REG_SCROLL, (uint8_t*)&offset, 4);
   }
 

drivers/dv_display/dv_display.hpp

@@ -148,8 +148,6 @@ namespace pimoroni {
 
       // Set the top left corner of the display within the frame, if a larger
       // frame is specified than the display.
-      // Note that the supplied x coordinate is rounded down to the previous multiple of 2 in RGB555 mode 
-      // or multiple of 4 in palette or RGB888 modes
       void set_display_offset(const Point& p);
 
       uint8_t get_gpio();

examples/dv_stick/dv_stick_test.cpp

@@ -9,18 +9,18 @@
 
 using namespace pimoroni;
 
-#define DISPLAY_WIDTH 720
+#define DISPLAY_WIDTH 360
 #define DISPLAY_HEIGHT 480
 
-#define FRAME_WIDTH 720
-#define FRAME_HEIGHT 720
+#define FRAME_WIDTH 1000
+#define FRAME_HEIGHT 480
 
 #define READ_EDID 0
 #if READ_EDID
 extern "C" { int decode_edid(unsigned char* edid); }
 #endif
 
-#define USE_PALETTE 1
+#define USE_PALETTE 0
 
 void on_uart_rx() {
     while (uart_is_readable(uart1)) {
@@ -205,11 +205,19 @@ int main() {
     //printf("%02x %02x\n", display.get_gpio(), display.get_gpio_hi());
 
     display.set_display_offset(scroll);
+    #if 1
+    scroll.x += scroll_dir;
+    if (scroll.x + DISPLAY_WIDTH > FRAME_WIDTH || scroll.x < 0) {
+      scroll_dir = -scroll_dir;
+      scroll.x += scroll_dir;
+    }
+    #else
     scroll.y += scroll_dir;
     if (scroll.y + DISPLAY_HEIGHT > FRAME_HEIGHT || scroll.y < 0) {
       scroll_dir = -scroll_dir;
       scroll.y += scroll_dir;
     }
+    #endif
 
     ++frames;
     display.set_gpio_hi_pull_up_all(frames & 0x3F);