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import * as _ from 'lodash';
import * as React from 'react';
import { ColorOption } from '../style/theme';
import { util } from '../util/util';
import { Input } from './ui/input';
export enum ScalingInputPhase {
FixedFontSize,
ScalingFontSize,
}
export interface ScalingSettings {
percentageToReduceFontSizePerCharacter: number;
constantPxToIncreaseWidthPerCharacter: number;
}
export interface ScalingInputProps {
textLengthThreshold: number;
maxFontSizePx: number;
value: string;
emptyInputWidthCh: number;
onChange: (event: React.ChangeEvent<HTMLInputElement>) => void;
onFontSizeChange: (fontSizePx: number) => void;
fontColor?: ColorOption;
placeholder?: string;
maxLength?: number;
scalingSettings: ScalingSettings;
isDisabled: boolean;
hasAutofocus: boolean;
}
export interface ScalingInputState {
inputWidthPxAtPhaseChange?: number;
}
export interface ScalingInputSnapshot {
inputWidthPx: number;
}
// These are magic numbers that were determined experimentally.
const defaultScalingSettings: ScalingSettings = {
percentageToReduceFontSizePerCharacter: 0.125,
constantPxToIncreaseWidthPerCharacter: 4,
};
export class ScalingInput extends React.Component<ScalingInputProps, ScalingInputState> {
public static defaultProps = {
onChange: util.boundNoop,
onFontSizeChange: util.boundNoop,
maxLength: 7,
scalingSettings: defaultScalingSettings,
isDisabled: false,
hasAutofocus: false,
};
public state: ScalingInputState = {
inputWidthPxAtPhaseChange: undefined,
};
private readonly _inputRef = React.createRef<HTMLInputElement>();
public static getPhase(textLengthThreshold: number, value: string): ScalingInputPhase {
if (value.length <= textLengthThreshold) {
return ScalingInputPhase.FixedFontSize;
}
return ScalingInputPhase.ScalingFontSize;
}
public static getPhaseFromProps(props: ScalingInputProps): ScalingInputPhase {
const { value, textLengthThreshold } = props;
return ScalingInput.getPhase(textLengthThreshold, value);
}
public static calculateFontSize(
textLengthThreshold: number,
maxFontSizePx: number,
phase: ScalingInputPhase,
value: string,
percentageToReduceFontSizePerCharacter: number,
): number {
if (phase !== ScalingInputPhase.ScalingFontSize) {
return maxFontSizePx;
}
const charactersOverMax = value.length - textLengthThreshold;
const scalingFactor = (1 - percentageToReduceFontSizePerCharacter) ** charactersOverMax;
const fontSize = scalingFactor * maxFontSizePx;
return fontSize;
}
public static calculateFontSizeFromProps(props: ScalingInputProps, phase: ScalingInputPhase): number {
const { textLengthThreshold, value, maxFontSizePx, scalingSettings } = props;
return ScalingInput.calculateFontSize(
textLengthThreshold,
maxFontSizePx,
phase,
value,
scalingSettings.percentageToReduceFontSizePerCharacter,
);
}
public getSnapshotBeforeUpdate(): ScalingInputSnapshot {
return {
inputWidthPx: this._getInputWidthInPx(),
};
}
public componentDidMount(): void {
// Trigger an initial notification of the calculated fontSize.
const currentPhase = ScalingInput.getPhaseFromProps(this.props);
const currentFontSize = ScalingInput.calculateFontSizeFromProps(this.props, currentPhase);
this.props.onFontSizeChange(currentFontSize);
}
public componentDidUpdate(
prevProps: ScalingInputProps,
prevState: ScalingInputState,
snapshot: ScalingInputSnapshot,
): void {
const prevPhase = ScalingInput.getPhaseFromProps(prevProps);
const curPhase = ScalingInput.getPhaseFromProps(this.props);
// if we went from fixed to scaling, save the width from the transition
if (prevPhase !== ScalingInputPhase.ScalingFontSize && curPhase === ScalingInputPhase.ScalingFontSize) {
this.setState({
inputWidthPxAtPhaseChange: snapshot.inputWidthPx,
});
}
// if we went from scaling to fixed, revert back to scaling using `ch`
if (prevPhase === ScalingInputPhase.ScalingFontSize && curPhase !== ScalingInputPhase.ScalingFontSize) {
this.setState({
inputWidthPxAtPhaseChange: undefined,
});
}
const prevFontSize = ScalingInput.calculateFontSizeFromProps(prevProps, prevPhase);
const curFontSize = ScalingInput.calculateFontSizeFromProps(this.props, curPhase);
// If font size has changed, notify.
if (prevFontSize !== curFontSize) {
this.props.onFontSizeChange(curFontSize);
}
}
public render(): React.ReactNode {
const { hasAutofocus, isDisabled, fontColor, onChange, placeholder, value, maxLength } = this.props;
const phase = ScalingInput.getPhaseFromProps(this.props);
return (
<Input
ref={this._inputRef as any}
fontColor={fontColor}
onChange={onChange}
value={value}
placeholder={placeholder}
fontSize={`${this._calculateFontSize(phase)}px`}
width={this._calculateWidth(phase)}
maxLength={maxLength}
disabled={isDisabled}
autoFocus={hasAutofocus}
/>
);
}
private readonly _calculateWidth = (phase: ScalingInputPhase): string => {
const { value, textLengthThreshold, scalingSettings } = this.props;
if (_.isEmpty(value)) {
return `${this.props.emptyInputWidthCh}ch`;
}
switch (phase) {
case ScalingInputPhase.FixedFontSize:
return `${value.length}ch`;
case ScalingInputPhase.ScalingFontSize:
const { inputWidthPxAtPhaseChange } = this.state;
if (!_.isUndefined(inputWidthPxAtPhaseChange)) {
const charactersOverMax = value.length - textLengthThreshold;
const scalingAmount = scalingSettings.constantPxToIncreaseWidthPerCharacter * charactersOverMax;
const width = inputWidthPxAtPhaseChange + scalingAmount;
return `${width}px`;
}
return `${textLengthThreshold}ch`;
}
};
private readonly _calculateFontSize = (phase: ScalingInputPhase): number => {
return ScalingInput.calculateFontSizeFromProps(this.props, phase);
};
private readonly _getInputWidthInPx = (): number => {
const ref = this._inputRef.current;
if (!ref) {
return 0;
}
return ref.getBoundingClientRect().width;
};
}
|
