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Type preRenderBar

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This commit is contained in:
Jordan Eldredge 2020-04-07 22:02:58 -07:00
parent dd36504ad6
commit fe90c1bacd
2 changed files with 51 additions and 47 deletions
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51
js/components/Visualizer.tsx
View file

@ -6,6 +6,8 @@ import { useTypedSelector, useActionCreator } from "../hooks";
import VisualizerInner from "./VisualizerInner";
const PIXEL_DENSITY = 2;
const BAR_WIDTH = 3 * PIXEL_DENSITY;
const GRADIENT_COLOR_COUNT = 16;
type Props = {
analyser: AnalyserNode;
@ -18,7 +20,7 @@ function preRenderBg(
bgColor: string,
fgColor: string,
windowShade: boolean
) {
): HTMLCanvasElement {
// Off-screen canvas for pre-rendering the background
const bgCanvas = document.createElement("canvas");
bgCanvas.width = width;
@ -42,6 +44,48 @@ function preRenderBg(
return bgCanvas;
}
function preRenderBar(
height: number,
colors: string[],
renderHeight: number
): HTMLCanvasElement {
/**
* The order of the colours is commented in the file: the fist two colours
* define the background and dots (check it to see what are the dots), the
* next 16 colours are the analyzer's colours from top to bottom, the next
* 5 colours are the oscilloscope's ones, from center to top/bottom, the
* last colour is for the analyzer's peak markers.
*/
// Off-screen canvas for pre-rendering a single bar gradient
const barCanvas = document.createElement("canvas");
barCanvas.width = BAR_WIDTH;
barCanvas.height = height;
const offset = 2; // The first two colors are for the background;
const gradientColors = colors.slice(offset, offset + GRADIENT_COLOR_COUNT);
const barCanvasCtx = barCanvas.getContext("2d");
if (barCanvasCtx == null) {
throw new Error("Could not construct canvas context");
}
const multiplier = GRADIENT_COLOR_COUNT / renderHeight;
// In shade mode, the five colors are, from top to bottom:
// 214, 102, 0 -- 3
// 222, 165, 24 -- 6
// 148, 222, 33 -- 9
// 57, 181, 16 -- 12
// 24, 132, 8 -- 15
// TODO: This could probably be improved by iterating backwards
for (let i = 0; i < renderHeight; i++) {
const colorIndex = GRADIENT_COLOR_COUNT - 1 - Math.floor(i * multiplier);
barCanvasCtx.fillStyle = gradientColors[colorIndex];
const y = height - i * PIXEL_DENSITY;
barCanvasCtx.fillRect(0, y, BAR_WIDTH, PIXEL_DENSITY);
}
return barCanvas;
}
function Visualizer(props: Props) {
const colors = useTypedSelector(Selectors.getSkinColors);
const style = useTypedSelector(Selectors.getVisualizerStyle);
@ -67,6 +111,10 @@ function Visualizer(props: Props) {
);
}, [colors, height, width, windowShade]);
const barCanvas = useMemo(() => {
return preRenderBar(height, colors, renderHeight);
}, [colors, height, renderHeight]);
const innerProps = {
width: renderWidth,
height: renderHeight,
@ -77,6 +125,7 @@ function Visualizer(props: Props) {
dummyVizData,
toggleVisualizerStyle,
bgCanvas,
barCanvas,
};
return <VisualizerInner {...innerProps} {...props} />;
}

47
js/components/VisualizerInner.js
View file

@ -6,7 +6,6 @@ const PIXEL_DENSITY = 2;
const NUM_BARS = 20;
const BAR_WIDTH = 3 * PIXEL_DENSITY;
const BAR_PEAK_DROP_RATE = 0.01;
const GRADIENT_COLOR_COUNT = 16;
const PEAK_COLOR_INDEX = 23;
// Return the average value in a slice of dataArray
@ -40,40 +39,6 @@ function octaveBucketsForBufferLength(bufferLength) {
return octaveBuckets;
}
function preRenderBar(height, colors, renderHeight) {
/**
* The order of the colours is commented in the file: the fist two colours
* define the background and dots (check it to see what are the dots), the
* next 16 colours are the analyzer's colours from top to bottom, the next
* 5 colours are the oscilloscope's ones, from center to top/bottom, the
* last colour is for the analyzer's peak markers.
*/
// Off-screen canvas for pre-rendering a single bar gradient
const barCanvas = document.createElement("canvas");
barCanvas.width = BAR_WIDTH;
barCanvas.height = height;
const offset = 2; // The first two colors are for the background;
const gradientColors = colors.slice(offset, offset + GRADIENT_COLOR_COUNT);
const barCanvasCtx = barCanvas.getContext("2d");
const multiplier = GRADIENT_COLOR_COUNT / renderHeight;
// In shade mode, the five colors are, from top to bottom:
// 214, 102, 0 -- 3
// 222, 165, 24 -- 6
// 148, 222, 33 -- 9
// 57, 181, 16 -- 12
// 24, 132, 8 -- 15
// TODO: This could probably be improved by iterating backwards
for (let i = 0; i < renderHeight; i++) {
const colorIndex = GRADIENT_COLOR_COUNT - 1 - Math.floor(i * multiplier);
barCanvasCtx.fillStyle = gradientColors[colorIndex];
const y = height - i * PIXEL_DENSITY;
barCanvasCtx.fillRect(0, y, BAR_WIDTH, PIXEL_DENSITY);
}
return barCanvas;
}
class VisualizerInner extends React.Component {
componentDidMount() {
@ -134,7 +99,6 @@ class VisualizerInner extends React.Component {
}
// TODO: Split this into to methods. One for skin update, one for style
// update.
this.preRenderBar();
this.props.analyser.fftSize = 2048;
if (this.props.style === VISUALIZERS.OSCILLOSCOPE) {
this.bufferLength = this.props.analyser.fftSize;
@ -149,15 +113,6 @@ class VisualizerInner extends React.Component {
}
}
// Pre-render the bar gradient
preRenderBar() {
this.barCanvas = preRenderBar(
this._height(),
this.props.colors,
this._renderHeight()
);
}
paintFrame() {
switch (this.props.style) {
case VISUALIZERS.OSCILLOSCOPE:
@ -222,7 +177,7 @@ class VisualizerInner extends React.Component {
// Draw the gradient
const b = BAR_WIDTH;
if (height > 0) {
ctx.drawImage(this.barCanvas, 0, y, b, height, x, y, b, height);
ctx.drawImage(this.props.barCanvas, 0, y, b, height, x, y, b, height);
}
// Draw the gray peak line