Fade In From Start

// Cavalry Script: Keyfast - Fade In from Start
// For each selected layer, animates opacity from 0 to 100 over 30 frames starting at layer in-point

var selectedLayers = api.getSelection();

if (selectedLayers.length === 0) {
    console.warn("No layers are selected. Please select some layers first.");
} else {
    var frameOffset = 30; // Number of frames for the animation
    console.info("Animating opacity (fade in from start) on " + selectedLayers.length + " selected layer(s)...");

    for (var i = 0; i < selectedLayers.length; i++) {
        var layerId = selectedLayers[i];
        var layerName = api.getNiceName(layerId);
        try {
            if (api.hasAttribute(layerId, "opacity")) {
                var start = api.getInFrame(layerId);
                var end = start + frameOffset;
                api.keyframe(layerId, start, {"opacity": 0});
                api.keyframe(layerId, end, {"opacity": 100});
                console.log("✓ " + layerName + ": Fade In from start (frames " + start + " → " + end + ")");
            } else {
                console.warn("✗ " + layerName + ": No opacity attribute");
            }
        } catch (error) {
            console.error("✗ Error processing " + layerName + ": " + error);
        }
    }
}