jpg_on_canvas.tc

jpg_on_canvas.tc — compose a JPG + procedural overlay into one canvas,

Source on GitHub

// jpg_on_canvas.tc — compose a JPG + procedural overlay into one canvas,
// then flip the composite to the panel with imgFlush.
//
// Demonstrates that TC 1.4.3 imgBlit accepts JPG-loaded image slots as a
// source (JPG and canvas slots share the same RGB565 storage), so the
// workflow is: decode once, paint anywhere.

int photo;
int scene;

void main() {
    // existing JPG already on the file system (change to whatever you have)
    photo = dspLoadImage("/gemu.jpg");
    if (photo < 0) {
        addLog("jpg_on_canvas: dspLoadImage failed");
        return;
    }

    int pw = dspImageWidth(photo);
    int ph = dspImageHeight(photo);

    scene = imgCreate(pw, ph);
    if (scene < 0) {
        addLog("jpg_on_canvas: imgCreate failed");
        return;
    }

    // dark background
    imgClear(scene, 0x0000);

    // paint the JPG into the canvas at (0,0)
    imgBlit(scene, photo, 0, 0, 0, 0, pw, ph);

    // overlay a bright rectangle + caption ON the canvas
    imgBeginDraw(scene);
        dspColor(0xF800, 0);   // red
        dspPos(8, ph - 30);
        dspFillRect(pw - 16, 22);
        dspColor(0xFFFF, 0xF800);
        dspPos(16, ph - 24);
        dspText("[f2]");
        dspDraw(" JPG + overlay via imgBlit ");
    imgEndDraw();

    // push the whole thing to the panel at (0,0) — whole canvas is dirty
    imgFlush(scene, 0, 0);
    addLog("jpg_on_canvas: composited");
}