移动PC图片拖拽缩放2
Posted yhquan
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// 获取图片 function getImage() { let modal = document.getElementById("modal"); getMainBox().addEventListener("click",function(e) { let event = getEvent(e); let target = event.target || event.srcElement; if(isImage(target)) { let imgUrl = target.getAttribute("src"); let str = `<img src="${imgUrl}" class="big-img" style="position: absolute; top: ${getImgInitPosition(target).top}px; left: ${getImgInitPosition(target).left}px; max-width: none; width: ${getImgInitPosition(target).width}px;cursor: move;" h="${getImgInitPosition(target).height}" w="${getImgInitPosition(target).width}"/>`; modal.innerhtml = str; modal.style.display = "block"; if(isMobile()) { zoomMobileImage() } } }) modal.addEventListener("click", function(e) { let event = getEvent(e); let target = event.target || event.srcElement; if(isImage(target)) { if(!isMobile()) { zoomWebImage(target); drageWebImage(); } } else { this.style.display = "none"; } }) } function zoomWebImage(img) { img.addEventListener("mousewheel", function(e) { mouseScroll(this, getEvent(e)); }); img.addEventListener("DOMMouseScroll", function(e) { mouseScroll(this, getEvent(e)); }) } function mouseScroll(img, e) { var oper = Math.max(-1, Math.min(1,(e.wheelDelta || -e.originalEvent.detail))); var imgWidth = img.style.width; if(!!imgWidth) { imgWidth = parseInt(imgWidth); var newWidth = Math.max(640, Math.min(1920, imgWidth + (30*oper))); var left = parseInt(img.style.left) - (newWidth - imgWidth) / 2; img.style.width = newWidth + "px"; img.style.left = left + "px"; } adjustImgPosition(img); } function zoomMobileImage() { let img = document.querySelector(".big-img"); var startX, startY, scaleStartX, scaleStartY, imgHeight, imgWidth, initTop, initLeft, originalHeight, originalWidth; let initHeight = parseInt(img.getAttribute("h")); let initWidth = parseInt(img.getAttribute("w")); let initVal = 30; // 防止图片拖出框内的最小边界值 let clientHeight = document.body.clientHeight; let clientWidth = document.body.clientWidth; let boxWidthMin = initVal; let boxWidthMax = parseInt(clientWidth) - initVal; let boxHeightMin = initVal; let boxHeightMax = parseInt(clientHeight) - initVal; img.addEventListener("touchstart", function(event) { preventDefaultEvt(event); let fingers = event.touches.length; let touch1 = event.targetTouches[0]; if(fingers === 2) { let touch2 = event.targetTouches[1]; originalHeight = parseInt(window.getComputedStyle(img).height); originalWidth = parseInt(window.getComputedStyle(img).width); scaleStartX = Math.abs(touch1.clientX - touch2.clientX); scaleStartY = Math.abs(touch1.clientY - touch2.clientY); } else if(fingers === 1) { startX = touch1.clientX; startY = touch1.clientY; initTop = parseInt(img.style.top); initLeft= parseInt(img.style.left); } }); img.addEventListener("touchmove", function(event) { preventDefaultEvt(event); let touch1 = event.targetTouches[0]; let fingers = event.touches.length; if (fingers === 2) { let touch2 = event.targetTouches[1]; let scaleEndX = Math.abs(touch1.clientX - touch2.clientX); let scaleEndY = Math.abs(touch1.clientY - touch2.clientY); let scaleX = parseInt(scaleEndX) - parseInt(scaleStartX); let scaleY = parseInt(scaleEndY) - parseInt(scaleStartY); let width = scaleX + originalWidth; let height = scaleY + originalHeight; if(width < initWidth || height < initHeight) { width = initWidth; height = initHeight; originalHeight = initHeight; } if(Math.abs(scaleX) > Math.abs(scaleY)) { img.style.width = width + "px"; } else { img.style.width = (height / originalHeight) * width + "px"; } adjustImgPosition(img); } else if(fingers === 1) { let clientX = touch1.clientX; let clientY = touch1.clientY; if(clientY >= boxHeightMin && clientY <= boxHeightMax) { img.style.top = initTop + clientY - startY + "px"; } if(clientX >= boxWidthMin && clientX <= boxWidthMax) { img.style.left = initLeft + clientX - startX + "px"; } } }); } function getImgInitPosition(img) { let clientHeight = document.body.clientHeight; let clientWidth = document.body.clientWidth; let width = isMobile() ? 340 : 640; let imgHeight = window.getComputedStyle(img).height; return { top: (parseInt(clientHeight) - parseInt(imgHeight)) / 2, left: (parseInt(clientWidth) - width) / 2, width: parseInt(width), height: parseInt(imgHeight) }; } function adjustImgPosition(img) { let clientHeight = document.body.clientHeight; let clientWidth = document.body.clientWidth; let imgHeight = window.getComputedStyle(img).height; let imgWidth = window.getComputedStyle(img).width; if(!!clientHeight) { var top = (parseInt(clientHeight) - parseInt(imgHeight)) / 2; var left = (parseInt(clientWidth) - parseInt(imgWidth)) / 2; img.style.top = top + ‘px‘; img.style.left = left + ‘px‘; } } function isMobile() { return !!(navigator.userAgent.match(/(phone|pad|pod|iPhone|iPod|ios|iPad|android|Mobile|BlackBerry|IEMobile|MQQBrowser|JUC|Fennec|wOSBrowser|BrowserNG|WebOS|Symbian|Windows Phone)/i)); } function getEvent(e) { return e || window.event; } function drageWebImage() { (function() { var isDrag = false; var dragTarget; var startX, startY; var imgPositionTop,imgPositionLeft; var boxWidthMin, boxWidthMax, boxHeightMin, boxHeightMax; function initDrag(e) { let event = getEvent(e); let dragHandle = event.target || event.srcElement; var topElement = "HTML"; var eventBtn = event.button == 0 || event.button == 1 if(isMobile()) { eventBtn = true; } while (dragHandle.tagName != topElement && dragHandle.className != "big-img") { dragHandle = dragHandle.parentElement; } if (dragHandle.className == "big-img" && eventBtn) { isDrag = true; dragTarget = dragHandle; imgPositionTop = parseInt(dragTarget.style.top); startY = event.clientY || event.pageY; imgPositionLeft = parseInt(dragTarget.style.left); startX = event.clientX || event.pageX; let initVal = 50; // 防止图片拖出框内的最小边界值 let clientHeight = document.body.clientHeight; let clientWidth = document.body.clientWidth; boxWidthMin = initVal; boxWidthMax = parseInt(clientWidth) - initVal; boxHeightMin = initVal; boxHeightMax = parseInt(clientHeight) - initVal; document.addEventListener("mousemove", moveMouse) return false; } function moveMouse(e) { let event = getEvent(e); if (isDrag) { var clientY = event.clientY; var clientX = event.clientX; if(clientY >= boxHeightMin && clientY <= boxHeightMax) { dragTarget.style.top = imgPositionTop + clientY - startY + "px"; } if(clientX >= boxWidthMin && clientX <= boxWidthMax) { dragTarget.style.left = imgPositionLeft + clientX - startX + "px"; } return false; } } } document.addEventListener("mousedown", initDrag) document.addEventListener("mouseup", function() { isDrag = false; }) })(); } function preventDefaultEvt(event) { if(event && event.preventDefault) { event.preventDefault(); } else { window.event.returnValue = false; return false } } getImage();
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