function renderWave()

in editor/extension.ts [258:330]

• 63 lines of code
• 7 McCabe index (conditional complexity)

                function renderWave(e: any) {
                    let aud = e.target;
                    let current = aud.currentTime;
                    let end = aud.duration;
                    let canvas = getCanvas();

                    if (!canvas || !canvas.getContext || !modController || !end) {
                        return;
                    }

                    let strip = canvas.getContext("2d");

                    // Resize the canvas to be the window size.
                    canvas.width = window.innerWidth;
                    canvas.height = window.innerHeight;

                    let h = strip.canvas.height;
                    let w = strip.canvas.width;
                    strip.clearRect(0, 0, w, h);

                    let y: number;
                    // Draw scale lines at 10% interval
                    strip.lineWidth = 1.0;
                    strip.strokeStyle = "#55a";
                    strip.beginPath();
                    y = 1 * (h / 10);
                    strip.moveTo(0, y);
                    strip.lineTo(w, y);
                    y = 2 * (h / 10);
                    strip.moveTo(0, y);
                    strip.lineTo(w, y);
                    y = 3 * (h / 10);
                    strip.moveTo(0, y);
                    strip.lineTo(w, y);
                    y = 4 * (h / 10);
                    strip.moveTo(0, y);
                    strip.lineTo(w, y);
                    y = 5 * (h / 10);
                    strip.moveTo(0, y);
                    strip.lineTo(w, y);
                    y = 6 * (h / 10);
                    strip.moveTo(0, y);
                    strip.lineTo(w, y);
                    y = 7 * (h / 10);
                    strip.moveTo(0, y);
                    strip.lineTo(w, y);
                    y = 8 * (h / 10);
                    strip.moveTo(0, y);
                    strip.lineTo(w, y);
                    y = 9 * (h / 10);
                    strip.moveTo(0, y);
                    strip.lineTo(w, y);
                    strip.stroke();

                    strip.strokeStyle = "#fff";
                    strip.lineWidth = 1.0;

                    let buffer = modController.getPcmData();
                    let b = Math.floor(buffer.length * ((current * 1.0) / end));
                    let lastSample = (buffer[b++] + 32768) / 65536.0; // map -32768..32768 to 0..1

                    for (let x = 1; x < canvas.width; x++) {
                        let sample = (buffer[b++] + 32768) / 65536.0;
                        if (b > buffer.length) {
                            break;
                        }
                        strip.beginPath();
                        strip.moveTo(x - 1, h - lastSample * h);
                        strip.lineTo(x, h - sample * h);
                        strip.stroke();
                        lastSample = sample;
                    }
                }