Two modes: DISPLAY_MODE_SAFE and DISPLAY_MODE_RAW
1 or 2 frame buffers (buffer_count)
Non-blocking and blocking frame acquisition:
- display_begin_paint_try()
- display_begin_paint_blocking()
Safe frame completion via display_end_paint()
Rendering primitives and a font module with Cyrillic support

Repository Structure

include/display/ - public headers for the engine and renderer
src/core/display.c - display engine core
src/render/ - primitives implementation
include/Font/, src/Font/ - font data and text rendering
Examples/Thermometr/ - working Pico SDK example project

Quick Start

1. Safe mode with a single display loop

Good for a simple loop where dropping a frame is acceptable when the buffer is busy.

#include "display/display.h"
#include "display/render/context.h"

#define WIDTH  320
#define HEIGHT 240

void app_loop(void) {
    display_config_t cfg = {
        .width = WIDTH,
        .height = HEIGHT,
        .buffer_count = 1,
        .mode = DISPLAY_MODE_SAFE
    };
    display_init(&cfg);

    render_ctx_t rc;

    while (1) {
        uint16_t *buf = display_begin_paint_try();
        if (!buf) {
            continue;
        }

        render_begin(&rc, buf, WIDTH, HEIGHT);
        render_clear(&rc, RGB16(0, 0, 0));
        // draw...

        bool ok = display_end_paint();
        hard_assert(ok);
    }
}

2. Safe mode with two buffers and deferred submit support

In SAFE + buffer_count = 2, DMA can scan out one buffer while you render the other one.
If DMA is busy at display_end_paint(), the frame may be deferred (single pending-frame queue).

#include "display/display.h"
#include "display/render/context.h"

#define WIDTH  320
#define HEIGHT 240

void app_loop(void) {
    display_config_t cfg = {
        .width = WIDTH,
        .height = HEIGHT,
        .buffer_count = 2,
        .mode = DISPLAY_MODE_SAFE
    };
    display_init(&cfg);

    render_ctx_t rc;

    while (1) {
        uint16_t *buf = display_begin_paint_try();
        if (!buf) {
            // DMA/queue busy: run other app logic
            continue;
        }

        render_begin(&rc, buf, WIDTH, HEIGHT);
        render_clear(&rc, RGB16(8, 16, 8));
        // draw...

        bool accepted = display_end_paint();
        hard_assert(accepted); // false only on contract misuse
    }
}

3. Primitive and font headers + output example

Minimal include set:

#include "display/display.h"
#include "display/renderer.h"          // aggregates context + line + grid + sine_wave + bezier
#include "Font/font_data.h"            // draw_string(), draw_char(), get_char_width()

Equivalent per-header includes:

#include "display/render/context.h"
#include "display/render/line.h"
#include "display/render/grid.h"
#include "display/render/sine_wave.h"
#include "display/render/bezier.h"
#include "Font/font_data.h"

Primitive + text render example:

render_ctx_t rc;
render_begin(&rc, buf, 320, 240);

render_clear(&rc, RGB16(9, 19, 9));
render_grid(&rc, 20, 20, 40, RGB16(12, 26, 13));
render_line(&rc, 0, 0, 319, 239, RGB16(255, 0, 0));
render_sine_wave(&rc, 960, 100, 2.0f, 0, 120, phase, RGB16(0, 255, 0));

int px[4] = {20, 80, 140, 220};
int py[4] = {200, 120, 220, 160};
render_bezier(&rc, px, py, 4, RGB16(255, 255, 0));

draw_string(&rc, 16, 16, L"Cyrillic check", RGB565(255, 255, 255));

Build Example (Pico SDK)

cd Examples/Thermometr
mkdir -p build && cd build
cmake ..
cmake --build .

Display pins are configured in Examples/Thermometr/CMakeLists.txt via target_compile_definitions(...): SPI_PORT, PIN_MOSI, PIN_SCK, PIN_CS, PIN_DC, PIN_RST, PIN_BL.

API Contract (Important)

Every successful display_begin_paint_*() must be followed by display_end_paint()
Do not call a second begin until the current paint section is closed
Do not call display_submit() manually inside an open paint section

Detailed usage scenarios: SCENARIOS.ru.md.