/**
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* 判断手指触摸位置
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*/
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export function determineDirection(clipX, clipY, clipWidth, clipHeight, currentX, currentY) {
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/*
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* (右下>>1 右上>>2 左上>>3 左下>>4)
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*/
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let corner;
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/**
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* 思路：（利用直角坐标系）
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* 1.找出裁剪框中心点
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* 2.如点击坐标在上方点与左方点区域内，则点击为左上角
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* 3.如点击坐标在下方点与右方点区域内，则点击为右下角
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* 4.其他角同理
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*/
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const mainPoint = [clipX + clipWidth / 2, clipY + clipHeight / 2]; // 中心点
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const currentPoint = [currentX, currentY]; // 触摸点
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if (currentPoint[0] <= mainPoint[0] && currentPoint[1] <= mainPoint[1]) {
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corner = 3; // 左上
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} else if (currentPoint[0] >= mainPoint[0] && currentPoint[1] <= mainPoint[1]) {
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corner = 2; // 右上
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} else if (currentPoint[0] <= mainPoint[0] && currentPoint[1] >= mainPoint[1]) {
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corner = 4; // 左下
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} else if (currentPoint[0] >= mainPoint[0] && currentPoint[1] >= mainPoint[1]) {
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corner = 1; // 右下
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}
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return corner;
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}
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/**
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* 图片边缘检测检测时，计算图片偏移量
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*/
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export function calcImageOffset(data, scale) {
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let left = data.imageLeft;
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let top = data.imageTop;
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scale = scale || data.scale;
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let imageWidth = data.imageWidth;
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let imageHeight = data.imageHeight;
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if ((data.angle / 90) % 2) {
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imageWidth = data.imageHeight;
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imageHeight = data.imageWidth;
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}
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const {
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clipX,
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clipWidth,
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clipY,
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clipHeight
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} = data;
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// 当前图片宽度/高度
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const currentImageSize = (size) => (size * scale) / 2;
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const currentImageWidth = currentImageSize(imageWidth);
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const currentImageHeight = currentImageSize(imageHeight);
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left = clipX + currentImageWidth >= left ? left : clipX + currentImageWidth;
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left = clipX + clipWidth - currentImageWidth <= left ? left : clipX + clipWidth - currentImageWidth;
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top = clipY + currentImageHeight >= top ? top : clipY + currentImageHeight;
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top = clipY + clipHeight - currentImageHeight <= top ? top : clipY + clipHeight - currentImageHeight;
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return {
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left,
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top,
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scale
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};
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}
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/**
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* 图片边缘检测时，计算图片缩放比例
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*/
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export function calcImageScale(data, scale) {
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scale = scale || data.scale;
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let {
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imageWidth,
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imageHeight,
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clipWidth,
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clipHeight,
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angle
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} = data
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if ((angle / 90) % 2) {
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imageWidth = imageHeight;
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imageHeight = imageWidth;
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}
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if (imageWidth * scale < clipWidth) {
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scale = clipWidth / imageWidth;
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}
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if (imageHeight * scale < clipHeight) {
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scale = Math.max(scale, clipHeight / imageHeight);
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}
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return scale;
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}
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/**
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* 计算图片尺寸
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*/
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export function calcImageSize(width, height, data) {
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let imageWidth = width,
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imageHeight = height;
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let {
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clipWidth,
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clipHeight,
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sysinfo,
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width: originWidth,
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height: originHeight
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} = data
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if (imageWidth && imageHeight) {
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if (imageWidth / imageHeight > (clipWidth || originWidth) / (clipWidth || originHeight)) {
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imageHeight = clipHeight || originHeight;
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imageWidth = (width / height) * imageHeight;
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} else {
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imageWidth = clipWidth || originWidth;
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imageHeight = (height / width) * imageWidth;
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}
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} else {
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let sys = sysinfo || uni.getSystemInfoSync();
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imageWidth = sys.windowWidth;
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imageHeight = 0;
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}
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return {
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imageWidth,
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imageHeight
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};
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}
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/**
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* 勾股定理求斜边
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*/
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export function calcPythagoreanTheorem(width, height) {
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return Math.sqrt(Math.pow(width, 2) + Math.pow(height, 2));
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}
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/**
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* 拖动裁剪框时计算
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*/
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export function clipTouchMoveOfCalculate(data, event) {
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const clientX = event.touches[0].clientX;
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const clientY = event.touches[0].clientY;
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let {
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clipWidth,
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clipHeight,
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clipY: oldClipY,
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clipX: oldClipX,
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clipStart,
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isLockRatio,
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maxWidth,
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minWidth,
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maxHeight,
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minHeight
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} = data;
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maxWidth = maxWidth / 2;
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minWidth = minWidth / 2;
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minHeight = minHeight / 2;
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maxHeight = maxHeight / 2;
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let width = clipWidth,
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height = clipHeight,
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clipY = oldClipY,
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clipX = oldClipX,
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// 获取裁剪框实际宽度/高度
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// 如果大于最大值则使用最大值
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// 如果小于最小值则使用最小值
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sizecorrect = () => {
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width = width <= maxWidth ? (width >= minWidth ? width : minWidth) : maxWidth;
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height = height <= maxHeight ? (height >= minHeight ? height : minHeight) : maxHeight;
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},
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sizeinspect = () => {
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sizecorrect();
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if ((width > maxWidth || width < minWidth || height > maxHeight || height < minHeight) && isLockRatio) {
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return false;
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} else {
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return true;
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}
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};
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//if (clipStart.corner) {
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height = clipStart.height + (clipStart.corner > 1 && clipStart.corner < 4 ? 1 : -1) * (clipStart.y - clientY);
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//}
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switch (clipStart.corner) {
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case 1:
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width = clipStart.width - clipStart.x + clientX;
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if (isLockRatio) {
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height = width / (clipWidth / clipHeight);
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}
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if (!sizeinspect()) return;
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break;
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case 2:
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width = clipStart.width - clipStart.x + clientX;
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if (isLockRatio) {
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height = width / (clipWidth / clipHeight);
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}
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if (!sizeinspect()) {
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return;
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} else {
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clipY = clipStart.clipY - (height - clipStart.height);
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}
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break;
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case 3:
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width = clipStart.width + clipStart.x - clientX;
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if (isLockRatio) {
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height = width / (clipWidth / clipHeight);
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}
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if (!sizeinspect()) {
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return;
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} else {
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clipY = clipStart.clipY - (height - clipStart.height);
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clipX = clipStart.clipX - (width - clipStart.width);
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}
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break;
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case 4:
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width = clipStart.width + clipStart.x - clientX;
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if (isLockRatio) {
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height = width / (clipWidth / clipHeight);
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}
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if (!sizeinspect()) {
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return;
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} else {
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clipX = clipStart.clipX - (width - clipStart.width);
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}
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break;
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default:
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break;
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}
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return {
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width,
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height,
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clipX,
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clipY
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};
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}
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/**
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* 单指拖动图片计算偏移
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*/
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export function imageTouchMoveOfCalcOffset(data, clientXForLeft, clientYForLeft) {
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let left = clientXForLeft - data.touchRelative[0].x,
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top = clientYForLeft - data.touchRelative[0].y;
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return {
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left,
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top
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};
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}
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