ViewfinderView.java 文件源码

private void drawScanLine(Canvas canvas, Rect frame) {
    Shader shader = new RadialGradient(
            (float)(frame.left + frame.width() / 2),
            (float)(scannerStart + SCANNER_LINE_HEIGHT / 2),
            360f,
            laserColor,
            shadeColor(laserColor),
            Shader.TileMode.MIRROR);
    paint.setAlpha(CURRENT_POINT_OPACITY);
    paint.setShader(shader);
    if (scannerStart <= scannerEnd) {
        canvas.drawRect(frame.left, scannerStart, frame.right, scannerStart + SCANNER_LINE_HEIGHT, paint);
        scannerStart += SCANNER_LINE_MOVE_DISTANCE;
    } else {
        scannerStart = frame.top;
    }
    paint.setShader(null);
}