31 lines
999 B
JavaScript
31 lines
999 B
JavaScript
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/** 保持纵横比缩放图片，使图片的长边能完全显示出来。也就是说，可以完整地将图片显示出来。
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* @param {Number} sx 固定盒子的x坐标,sy 固定盒子的y左标
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* @param {Number} box_w 固定盒子的宽, box_h 固定盒子的高
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* @param {Number} source_w 原图片的宽, source_h 原图片的高
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* @return {Object} {drawImage的参数，缩放后图片的x坐标，y坐标，宽和高},对应drawImage(imageResource, dx, dy, dWidth, dHeight)
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*/
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const containImg = (sx, sy, box_w, box_h, source_w, source_h) => {
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var dx = sx,
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dy = sy,
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dWidth = box_w,
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dHeight = box_h;
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if (source_w > source_h || (source_w == source_h && box_w < box_h)) {
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dHeight = source_h * dWidth / source_w;
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dy = sy + (box_h - dHeight) / 2;
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} else if (source_w < source_h || (source_w == source_h && box_w > box_h)) {
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dWidth = source_w * dHeight / source_h;
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dx = sx + (box_w - dWidth) / 2;
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}
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return {
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dx,
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dy,
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dWidth,
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dHeight
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}
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}
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export {
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containImg
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}
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