Quantum Painter is the standardised API for graphical displays. It currently includes support for basic drawing primitives, as well as custom images, animations, and fonts.
Due to the complexity, there is no support for Quantum Painter on AVR-based boards.
To enable overall Quantum Painter to be built into your firmware, add the following to `rules.mk`:
Quantum Painter is not currently integrated with system-level operations such as when the keyboard goes into suspend. Users will need to handle this manually at the current time.
| `QUANTUM_PAINTER_DISPLAY_TIMEOUT` | `30000` | This controls the amount of time (in milliseconds) that all displays will remain on after the last user input. If set to `0`, the display will remain on indefinitely. |
| `QUANTUM_PAINTER_TASK_THROTTLE` | `1` | This controls the amount of time (in milliseconds) that the Quantum Painter internal task will wait between each execution. Affects animations, display timeout, and LVGL timing if enabled. |
| `QUANTUM_PAINTER_NUM_IMAGES` | `8` | The maximum number of images/animations that can be loaded at any one time. |
| `QUANTUM_PAINTER_NUM_FONTS` | `4` | The maximum number of fonts that can be loaded at any one time. |
| `QUANTUM_PAINTER_CONCURRENT_ANIMATIONS` | `4` | The maximum number of animations that can be executed at the same time. |
| `QUANTUM_PAINTER_LOAD_FONTS_TO_RAM` | `FALSE` | Whether or not fonts should be loaded to RAM. Relevant for fonts stored in off-chip persistent storage, such as external flash. |
| `QUANTUM_PAINTER_PIXDATA_BUFFER_SIZE` | `1024` | The limit of the amount of pixel data that can be transmitted in one transaction to the display. Higher values require more RAM on the MCU. |
| `QUANTUM_PAINTER_SUPPORTS_256_PALETTE` | `FALSE` | If 256-color palettes are supported. Requires significantly more RAM on the MCU. |
| `QUANTUM_PAINTER_SUPPORTS_NATIVE_COLORS` | `FALSE` | If native color range is supported. Requires significantly more RAM on the MCU. |
| `QUANTUM_PAINTER_DEBUG` | _unset_ | Prints out significant amounts of debugging information to CONSOLE output. Significant performance degradation, use only for debugging. |
| `QUANTUM_PAINTER_DEBUG_ENABLE_FLUSH_TASK_OUTPUT` | _unset_ | By default, debug output is disabled while the internal task is flushing the display(s). If you want to keep it enabled, add this to your `config.h`. Note: Console will get clogged. |
There's another variant for this [Waveshare module](https://www.waveshare.com/wiki/3.5inch_TFT_Touch_Shield), because it has a quirky SPI->Parallel converter. You can create it with:
Some ST7735 devices are known to have different drawing offsets -- despite being a 132x162 pixel display controller internally, some display panels are only 80x160, or smaller. These may require an offset to be applied; see `qp_set_viewport_offsets` above for information on how to override the offsets if they aren't correctly rendered.
Some ST7789 devices are known to have different drawing offsets -- despite being a 240x320 pixel display controller internally, some display panels are only 240x240, or smaller. These may require an offset to be applied; see `qp_set_viewport_offsets` above for information on how to override the offsets if they aren't correctly rendered.
OLED displays tend to use 5-pin SPI when at larger resolutions, or when using color -- SPI SCK, SPI MOSI, SPI CS, D/C, and RST pins. Smaller OLEDs may use I2C instead.
When using these displays, either `spi_master` or `i2c_master` must already be correctly configured for both the platform and panel you're building for.
For SPI, the pin assignments for SPI CS, D/C, and RST are specified during device construction -- for I2C the panel's address is specified instead.
SSD1306 and SH1106 are almost entirely identical, to the point of being indisinguishable by Quantum Painter. Enable SH1106 support in Quantum Painter and create SH1106 devices in firmware to perform drawing operations on SSD1306 displays.
Quantum Painter has a surface driver which is able to target a buffer in RAM. In general, surfaces keep track of the "dirty" region -- the area that has been drawn to since the last flush -- so that when transferring to the display they can transfer the minimal amount of data to achieve the end result.
The `surface` is the surface to copy out from. The `display` is the target display to draw into. `x` and `y` are the target location to draw the surface pixel data. Under normal circumstances, the location should be consistent, as the dirty region is calculated with respect to the `x` and `y` coordinates -- changing those will result in partial, overlapping draws. `entire_surface` whether the entire surface should be drawn, instead of just the dirty region.
All APIs require a `painter_device_t` object as their first parameter -- this object comes from the specific device initialisation, and instructions on creating it can be found in each driver's respective section.
To use any of the APIs, you need to include `qp.h`:
The coordinate system used in Quantum Painter generally accepts `left`, `top`, `right`, and `bottom` instead of x/y/width/height, and each coordinate is inclusive of where pixels should be drawn. This is required as some datatypes used by display panels have a maximum value of `255` -- for any value or geometry extent that matches `256`, this would be represented as a `0`, instead.
The `qp_init` function is used to initialise a display device after it has been created. This accepts a rotation parameter (`QP_ROTATION_0`, `QP_ROTATION_90`, `QP_ROTATION_180`, `QP_ROTATION_270`), which makes sure that the orientation of what's drawn on the display is correct.
```c
static painter_device_t display;
void keyboard_post_init_kb(void) {
display = qp_make_.......; // Create the display
qp_init(display, QP_ROTATION_0); // Initialise the display
If there is a separate backlight controlled through the normal QMK backlight API, this is not controlled by the `qp_power` function and needs to be manually handled elsewhere.
The `qp_flush` function ensures that all drawing operations are "pushed" to the display. This should be done as the last operation whenever a sequence of draws occur, and guarantees that any changes are applied.
Some display panels may seem to work even without a call to `qp_flush` -- this may be because the driver cannot queue drawing operations and needs to display them immediately when invoked. In general, calling `qp_flush` at the end is still considered "best practice".
Using `qp_setpixel` for large amounts of drawing operations is inefficient and should be avoided unless they cannot be achieved with other drawing APIs.
The `qp_rect` can be used to draw rectangles on the screen with the supplied color, with or without a background fill. If not filled, any pixels inside the rectangle will be left as-is.
```c
void housekeeping_task_user(void) {
static uint32_t last_draw = 0;
if (timer_elapsed32(last_draw) > 33) { // Throttle to 30fps
last_draw = timer_read32();
// Draw 8px-wide rainbow filled rectangles down the left side of the display
for (int i = 0; i <239;i+=8){
qp_rect(display, 0, i, 7, i+7, i, 255, 255, true);
The `qp_circle` can be used to draw circles on the screen with the supplied color, with or without a background fill. If not filled, any pixels inside the circle will be left as-is.
```c
void housekeeping_task_user(void) {
static uint32_t last_draw = 0;
if (timer_elapsed32(last_draw) > 33) { // Throttle to 30fps
last_draw = timer_read32();
// Draw r=4 filled circles down the left side of the display
The `qp_ellipse` can be used to draw ellipses on the screen with the supplied color, with or without a background fill. If not filled, any pixels inside the ellipses will be left as-is.
```c
void housekeeping_task_user(void) {
static uint32_t last_draw = 0;
if (timer_elapsed32(last_draw) > 33) { // Throttle to 30fps
last_draw = timer_read32();
// Draw 16x8 filled ellipses down the left side of the display
for (int i = 0; i <239;i+=8){
qp_ellipse(display, 8, 4+i, 16, 8, i, 255, 255, true);
Making an image available for use requires compiling it into your firmware. To do so, assuming you've created `my_image.qgf.c` and `my_image.qgf.h` as per the CLI examples above, you'd add the following to your `rules.mk`:
```make
SRC += my_image.qgf.c
```
...and in your `keymap.c`, you'd add to the top of the file:
`qp_load_image_mem` returns a handle to the loaded image, which can then be used to draw to the screen using `qp_drawimage`, `qp_drawimage_recolor`, `qp_animate`, or `qp_animate_recolor`. If an image is no longer required, it can be unloaded by calling `qp_close_image` below.
The total number of images available to load at any one time is controlled by the configurable option `QUANTUM_PAINTER_NUM_IMAGES` in the table above. If more images are required, the number should be increased in `config.h`.
The `qp_drawimage` and `qp_drawimage_recolor` functions draw the supplied image to the screen at the supplied location, with the latter function allowing for monochrome-based images to be recolored.
```c
// Draw an image on the bottom-right of the 240x320 display on initialisation
The `qp_animate` and `qp_animate_recolor` functions draw the supplied image to the screen at the supplied location, with the latter function allowing for monochrome-based animations to be recolored. They also set up internal timing such that each frame is rendered at the correct time as per the animated image.
Once an image has been set to animate, it will loop indefinitely until stopped, with no user intervention required.
Both functions return a `deferred_token`, which can then be used to stop the animation, using `qp_stop_animation` below.
```c
// Animate an image on the bottom-right of the 240x320 display on initialisation
Making a font available for use requires compiling it into your firmware. To do so, assuming you've created `my_font.qff.c` and `my_font.qff.h` as per the CLI examples above, you'd add the following to your `rules.mk`:
```make
SRC += noto11.qff.c
```
...and in your `keymap.c`, you'd add to the top of the file:
`qp_load_font_mem` returns a handle to the loaded font, which can then be measured using `qp_textwidth`, or drawn to the screen using `qp_drawtext`, or `qp_drawtext_recolor`. If a font is no longer required, it can be unloaded by calling `qp_close_font` below.
The total number of fonts available to load at any one time is controlled by the configurable option `QUANTUM_PAINTER_NUM_FONTS` in the table above. If more fonts are required, the number should be increased in `config.h`.
The `qp_drawtext` and `qp_drawtext_recolor` functions draw the supplied string to the screen at the given location using the font supplied, with the latter function allowing for monochrome-based fonts to be recolored.
```c
// Draw a text message on the bottom-right of the 240x320 display on initialisation
The `qp_set_viewport_offsets` function can be used to offset all subsequent drawing operations. For example, if a display controller is internally 240x320, but the display panel is 240x240 and has a Y offset of 80 pixels, you could invoke `qp_set_viewport_offsets(display, 0, 80);` and the drawing positioning would be corrected.
The `qp_pixdata` function allows raw pixel data to be streamed to the display. It requires a native pixel count rather than the number of bytes to transfer, to ensure display panel data alignment is respected. E.g. for display panels using RGB565 internal format, sending 10 pixels will result in 20 bytes of transfer.
Under normal circumstances, users will not need to manually call either `qp_viewport` or `qp_pixdata`. These allow for writing of raw pixel information, in the display panel's native format, to the area defined by the viewport.
