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52 lines
1.8 KiB
TypeScript
52 lines
1.8 KiB
TypeScript
/*
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* @Author: ShawnPhang
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* @Date: 2023-10-05 16:33:07
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* @Description:
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* @LastEditors: ShawnPhang <https://m.palxp.cn>
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* @LastEditTime: 2023-10-08 11:10:19
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*/
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import { DRAWING_STEP_BASE, DRAWING_STEP_BASE_BASE, MIN_RADIUS } from '../constants'
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import { RectSize, TransformConfig } from '../types/common'
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const { sqrt, max } = Math
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export function fixed(num: number): number {
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return num | 0
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}
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// 比Math.hypot(x,y)快一些(在数量级较大的情况下)
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export function getRawDistance(xDistance: number, yDistance: number): number {
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return sqrt(xDistance ** 2 + yDistance ** 2)
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}
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/** 计算插值绘制的间隔步长 */
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export function computeStepBase(radius: number) {
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return radius / DRAWING_STEP_BASE_BASE
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}
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/** 计算真实(相对真实，如果图像分辨率会控制在2K以内以保证性能)尺寸的画笔绘制点的半径 */
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export function computeRealRadius(rawRadius: number, scaleRatio: number) {
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return max(MIN_RADIUS, rawRadius) / scaleRatio
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}
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/** 计算移动绘制的节流步长 */
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export function computeStep(radius: number) {
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return radius / DRAWING_STEP_BASE
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}
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/** 基于新的缩放比例计算新的绘制范围 */
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export function computeNewTransformConfigByScaleRatio(transformConfig: TransformConfig, pictureSize: RectSize, scaleRatio: number): TransformConfig {
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const { minX, minY } = transformConfig.positionRange
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const { width, height } = pictureSize
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const maxX = minX + width * scaleRatio
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const maxY = minY + height * scaleRatio
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return { positionRange: { minX, maxX, minY, maxY }, scaleRatio }
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}
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/** 获取图片缩放到画框区域内的实际尺寸 */
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export function computeScaledImageSize(imageSize: RectSize, scaleRatio: number): RectSize {
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return {
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width: imageSize.width * scaleRatio,
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height: imageSize.height * scaleRatio,
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}
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}
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