cam_view_lvgl.tc

cam_view_lvgl.tc — live ESP32-P4 camera on the LVGL screen, with ROTATION + sizing.

Source on GitHub

// cam_view_lvgl.tc — live ESP32-P4 camera on the LVGL screen, with ROTATION + sizing.
//
// LVGL has no JPEG decoder, but it CAN render a raw RGB565 buffer. The P4 MIPI-CSI
// camera gives JPEG → dspLoadImageFromCam HW-decodes it to RGB565 in PSRAM → we point
// an LVGL CANVAS at that buffer. A canvas IS an lv_image, so lvglImageScale (size) and
// lvglImageAngle (rotation) work on it — no file, no JPEG-in-LVGL.
//
// Needs ABI >= 14 firmware (lvglCanvas / lvglCanvasSetImgSlot / dspFreeImage),
// USE_TINYC_LVGL, and the P4 camera (USE_CSI_WEBCAM). Capture blocks → run it in
// TaskLoop (the VM task thread).

#define CAM_SLOT  1
#define ZOOM      64          // lvglImageScale: 256 = 100%, 64 = 25% (small thumbnail)

int canvas;
int cur;                      // image slot the canvas currently shows (-1 = none)
int g_zoom;
int g_angle;                  // rotation, 0.1° units (900 = 90°)
int frames;

int main() {
    cur     = -1;
    g_zoom  = ZOOM;
    g_angle = 0;
    frames  = 0;

    cameraInit("", 4, 8, 12, 0, 0, -1, -1);   // P4: pins/format/size fixed by the CSI driver

    lvglInit();
    lvglClean(0);
    lvglSetBgColor(0, 0x101418);

    canvas = lvglCanvas(0);                    // an lv_image subclass → it can rotate + scale
    lvglAlign(canvas, 2, 0, 120);              // 2 = top-mid, 120 px down

    addCommand("CAM");                         // "CAM <deci-deg>" rotates live; "CAM" reports
    addLog("cam_view_lvgl: ready (zoom=%d)", g_zoom);
    return 0;
}

void TaskLoop() {
    if (camControl(10, CAM_SLOT, 0) <= 0) { delay(200); return; }   // capture JPEG → PSRAM
    int img = dspLoadImageFromCam(CAM_SLOT);                        // HW-decode → RGB565 slot
    if (img < 0) { delay(200); return; }

    lvglCanvasSetImgSlot(canvas, img);         // LVGL shows the PSRAM frame (zero-copy)
    lvglImagePivot(canvas, 0, 0);
    lvglImageScale(canvas, g_zoom, g_zoom);    // size
    lvglImageAngle(canvas, g_angle);           // rotation

    if (cur >= 0) { dspFreeImage(cur); }        // free the previous frame's slot
    cur = img;
    frames = frames + 1;
    delay(120);                                 // a few FPS
}

void Command(char cmd[]) {
    int i = 0;
    int hasdigit = 0;
    while (cmd[i] != 0) { if (cmd[i] >= '0' && cmd[i] <= '9') { hasdigit = 1; } i = i + 1; }
    if (hasdigit == 1) { int a = atoi(cmd); if (a >= 0 && a < 3600) { g_angle = a; } }  // bare "CAM" just reports
    char r[56]; sprintf(r, "frames=%d angle=%d zoom=%d", frames, g_angle, g_zoom); responseCmnd(r);
}