Remove buffers from hline and vline

For some reason this is around 50% slower atm:

50178 -> 24871 vertical lines per second
63583 -> 34266 horizontal lines per second

hagl_hal_single.c

@@ -66,28 +66,13 @@ blit(void *self, int16_t x0, int16_t y0, hagl_bitmap_t *src)
 static void
 hline(void *self, int16_t x0, int16_t y0, uint16_t width, hagl_color_t color)
 {
-    static hagl_color_t line[HAGL_PICO_MIPI_DISPLAY_WIDTH];
-    const uint16_t height = 1;
-
-    for (uint16_t x = 0; x < width; x++) {
-        line[x] = color;
-
-    }
-
-    mipi_display_write(x0, y0, width, height, (uint8_t *) line);
+    mipi_display_fill(x0, y0, width, 1, &color);
 }
 
 static void
 vline(void *self, int16_t x0, int16_t y0, uint16_t height, hagl_color_t color)
 {
-    static hagl_color_t line[HAGL_PICO_MIPI_DISPLAY_HEIGHT];
-    const uint16_t width = 1;
-
-    for (uint16_t y = 0; y < height; y++) {
-        line[y] = color;
-    }
-
-    mipi_display_write(x0, y0, width, height, (uint8_t *) line);
+    mipi_display_fill(x0, y0, 1, height, &color);
 }
 
 void

include/mipi_display.h

@@ -45,6 +45,7 @@ extern "C" {
 
 void mipi_display_init();
 size_t mipi_display_write(uint16_t x1, uint16_t y1, uint16_t w, uint16_t h, uint8_t *buffer);
+size_t mipi_display_fill(uint16_t x1, uint16_t y1, uint16_t w, uint16_t h, void *color);
 void mipi_display_ioctl(uint8_t command, uint8_t *data, size_t size);
 void mipi_display_close();
 

mipi_display.c

@@ -266,6 +266,35 @@ void mipi_display_init()
 #endif /* HAGL_HAS_HAL_BACK_BUFFER */
 }
 
+size_t mipi_display_fill(uint16_t x1, uint16_t y1, uint16_t w, uint16_t h, void *color)
+{
+    if (0 == w || 0 == h) {
+        return 0;
+    }
+
+    int32_t x2 = x1 + w - 1;
+    int32_t y2 = y1 + h - 1;
+    size_t size = w * h;
+    uint8_t *c = color;
+
+    mipi_display_set_address(x1, y1, x2, y2);
+
+    /* Set DC high to denote incoming data. */
+    gpio_put(MIPI_DISPLAY_PIN_DC, 1);
+
+    /* Set CS low to reserve the SPI bus. */
+    gpio_put(MIPI_DISPLAY_PIN_CS, 0);
+
+    while (size--) {
+        spi_write_blocking(MIPI_DISPLAY_SPI_PORT, color, MIPI_DISPLAY_DEPTH / 8);
+    }
+
+    /* Set CS high to ignore any traffic on SPI bus. */
+    gpio_put(MIPI_DISPLAY_PIN_CS, 1);
+
+    return size;
+}
+
 size_t mipi_display_write(uint16_t x1, uint16_t y1, uint16_t w, uint16_t h, uint8_t *buffer)
 {
     if (0 == w || 0 == h) {