lvgl_demo.tc

lvgl_demo.tc — LVGL Phase 1 demo (requires firmware built with USE_TINYC_LVGL)

Source on GitHub

// lvgl_demo.tc — LVGL Phase 1 demo (requires firmware built with USE_TINYC_LVGL)
//
// Builds a tiny touch UI on the device panel: a label + a button. Tapping the button
// toggles the label text and the screen background. Demonstrates the Phase 1 API:
// object create, position/size/align/text/colour props, and the event poll ring.
//
// Handle 0 = the active screen (use it as a parent, or to style the screen itself).

#define LV_ALIGN_CENTER   9
#define LV_EVENT_CLICKED  10      // LVGL 9.5 enum value (NOT 7 — there are SINGLE/DOUBLE/TRIPLE_CLICKED before it)

int lbl;        // status label (on the screen)
int btn;        // the button
int on = 0;     // toggle state

int main() {
    lvglInit();                              // bring LVGL up on the panel
    lvglSetBgColor(0, 0x10243a);             // screen background (dark blue)

    lbl = lvglLabel(0);                       // label parented to the screen
    lvglSetText(lbl, "Tap the button");
    lvglSetTextColor(lbl, 0xFFFFFF);
    lvglAlign(lbl, LV_ALIGN_CENTER, 0, -50);

    btn = lvglButton(0);
    lvglSetSize(btn, 180, 60);
    lvglAlign(btn, LV_ALIGN_CENTER, 0, 30);
    lvglEventEnable(btn, LV_EVENT_CLICKED);   // route CLICKED into the poll ring

    int cap = lvglLabel(btn);                 // caption is a child of the button
    lvglSetText(cap, "PRESS");
    lvglAlign(cap, LV_ALIGN_CENTER, 0, 0);

    // poll loop — LVGL itself renders in the firmware FUNC_LOOP; we just react to events
    while (1) {
        while (lvglEvent()) {
            if (lvglEventObj() == btn && lvglEventCode() == LV_EVENT_CLICKED) {
                on = 1 - on;
                if (on) {
                    lvglSetText(lbl, "Button tapped!");
                    lvglSetBgColor(0, 0x0a3a1a);     // green
                } else {
                    lvglSetText(lbl, "Tap the button");
                    lvglSetBgColor(0, 0x10243a);     // blue
                }
            }
        }
        delay(30);
    }
    return 0;
}