移除上传的图片onclick文字

Question

一旦用户点击蒙版图片，我们就允许用户上传自定义图片....除了图片，我们还会显示文字 "Remove Image"... .

问题 :

单击该文本，我想像这样删除上传的图像 codepen1...但现在当我使用以下代码时，只有文本被删除：

var target;
var imageUrl = "https://i.imgur.com/RzEm1WK.png";

let jsonData = {  
  "layers" : [
    {
      "x" : 0,
      "height" : 612,   
      "layers" : [
        {
          "x" : 0,          
          "y" : 0,         
          "name" : "L2a"
        },
        {
          "x" : 160,         
          "layers" : [
            {
              "x" : 0,            
              "src" : "ax0HVTs.png",
              "y" : 0,              
              "name" : "L2b-1"
            },
            {
              
              "x" : 0,
              "y" : 0,             
              "name" : "L2b-2"
            }
          ],
          "y" : 291,         
          "name" : "user_image_1"
        },
        {
          "x" : 25,         
          "layers" : [
            {
              "x" : 0,             
              "src" : "hEM2kEP.png",
              "y" : 0,             
              "name" : "L2C-1"
            },
            {            
              "x" : 0,
              "y" : 0,            
              "name" : "L2C-2"
            }
          ],
          "y" :22,         
          "name" : "L2"
        }
      ],
      "y" : 0, 
      "width" : 612,   
      "name" : "L1"
    }
  ]
};

$(document).ready(function() {

    // below code will upload image onclick mask image

   $('.container').click(function(e) {

        var res = e.target;
        target = res.id;
        console.log(target);
        if (e.target.getContext) 
  {            
                setTimeout(() => {
                    $('#fileup').click();
                }, 20);           
        }
    });
 
 // Below code will fetch mask images from json file
 
    function getAllSrc(layers) {
        let arr = [];
        layers.forEach(layer => {
            if (layer.src) {
                arr.push({
                    src: layer.src,
                    x: layer.x,
                    y: layer.y,
     name: layer.name
                });
            } else if (layer.layers) {
                let newArr = getAllSrc(layer.layers);
                if (newArr.length > 0) {
                    newArr.forEach(({
                        src,
                        x,
                        y,
      name
                    }) => {
                        arr.push({
                            src,
                            x: (layer.x + x),
                            y: (layer.y + y),
       name: (name)
                        });
                    });
                }
            }
        });
        return arr;
    }

     function json(data)

        {
            var width = 0;
            var height = 0;

            let arr = getAllSrc(data.layers);

            let layer1 = data.layers;
            width = layer1[0].width;
            height = layer1[0].height;
            let counter = 0;
            let table = [];

            for (let {
                    src,
                    x,
                    y,
     name
                } of arr) {
                $(".container").css('width', width + "px").css('height', height + "px").addClass('temp');
                if(name.indexOf('mask_') !== -1){
                    var imageUrl1 = imageUrl;
                }else{
                    var imageUrl1 = '';
                }    
                var mask = $(".container").mask({                
       imageUrl: imageUrl1,     
                    maskImageUrl: 'https://i.imgur.com/' + src,
                    onMaskImageCreate: function(img) {

                        img.css({
                            "position": "absolute",
                            "left": x + "px",
                            "top": y + "px"
                        });

                    },
                    id: counter
                });
                table.push(mask);
                fileup.onchange = function() {

                    let mask2 = table[target];
                    mask2.loadImage(URL.createObjectURL(fileup.files[0]));
                    document.getElementById('fileup').value = "";
     
     // Below code to Remove image

                $("<span class=\"pip\">" +
                    "<img src='https://i.imgur.com/' + src  />" +
                    "<br/><span class=\"remove\">Remove image</span>" +
                    "</span>").insertAfter("#fileup");

                $(".remove").click(function() {
                    $(this).parent(".pip").remove();
                });

                // Remove image code ended here.... 
                };
                counter++;
    // get the text
    
            }
        }
json(jsonData);
}); // end of document ready

// jq plugin 

(function($) {
    var JQmasks = [];
    $.fn.mask = function(options) {
        // This is the easiest way to have default options.
        var settings = $.extend({
            // These are the defaults.
            maskImageUrl: undefined,
            imageUrl: undefined,
            scale: 1,
            id: new Date().getUTCMilliseconds().toString(),
            x: 0, // image start position
            y: 0, // image start position
            onMaskImageCreate: function(div) {},
        }, options);


        var container = $(this);

        let prevX = 0,
            prevY = 0,
            draggable = false,
            img,
            canvas,
            context,
            image,
            timeout,
            initImage = false,
            startX = settings.x,
            startY = settings.y,
            div;

        container.mousePosition = function(event) {
            return {
                x: event.pageX || event.offsetX,
                y: event.pageY || event.offsetY
            };
        }

        container.selected = function(ev) {
            var pos = container.mousePosition(ev);
            var item = $(".masked-img canvas").filter(function() {
                var offset = $(this).offset()
                var x = pos.x - offset.left;
                var y = pos.y - offset.top;
                var d = this.getContext('2d').getImageData(x, y, 1, 1).data;
                return d[0] > 0
            });

            JQmasks.forEach(function(el) {
                var id = item.length > 0 ? $(item).attr("id") : "";
                if (el.id == id)
                    el.item.enable();
                else el.item.disable();
            });
        };

        container.enable = function() {
            draggable = true;
            $(canvas).attr("active", "true");
            div.css({
                "z-index": 2
            });
        }

        container.disable = function() {
            draggable = false;
            $(canvas).attr("active", "false");
            div.css({
                "z-index": 1
            });
        }

        container.onDragStart = function(evt) {
            if (evt.target.getContext) {
                var pixel = evt.target.getContext('2d').getImageData(evt.offsetX, evt.offsetY, 1, 1).data;

                $(canvas).attr("active", "true");
                container.selected(evt);
                prevX = evt.clientX;
                prevY = evt.clientY;
                var img = new Image();
                evt.originalEvent.dataTransfer.setDragImage(img, 10, 10);
                evt.originalEvent.dataTransfer.setData('text/plain', 'anything');

            }
        };

        container.getImagePosition = function() {
            return {
                x: settings.x,
                y: settings.y,
                scale: settings.scale
            };
        };

        container.onDragOver = function(evt) {

            if (evt.target.getContext) {
                var pixel = evt.target.getContext('2d').getImageData(evt.offsetX, evt.offsetY, 1, 1).data;
                if (pixel[3] === 255) {
                    if (draggable && $(canvas).attr("active") === "true") {
                        var x = settings.x + evt.clientX - prevX;
                        var y = settings.y + evt.clientY - prevY;
                        if (x == settings.x && y == settings.y)
                            return; // position has not changed
                        settings.x += evt.clientX - prevX;
                        settings.y += evt.clientY - prevY;
                        prevX = evt.clientX;
                        prevY = evt.clientY;
                        clearTimeout(timeout);
                        timeout = setTimeout(function() {
                            container.updateStyle();
                            renderInnerImage();
                        }, 20);
                    }
                } else {
                    evt.stopPropagation();
                    return false;
                }
            }
        };

        container.updateStyle = function() {
            return new Promise((resolve, reject) => {
                context.beginPath();
                context.globalCompositeOperation = "source-over";
                image = new Image();
                image.setAttribute('crossOrigin', 'anonymous');
                image.src = settings.maskImageUrl;
                image.onload = function()
                {
                    canvas.width = image.width;
                    canvas.height = image.height;
                    context.drawImage(image, 0, 0, image.width, image.height);
                    div.css({
                        "width": image.width,
                        "height": image.height
                    });
                    resolve();
                };
            });
        };

        function renderInnerImage() {
            img = new Image();
            img.setAttribute('crossOrigin', 'anonymous');
            img.src = settings.imageUrl;
            img.onload = function() {
                settings.x = settings.x == 0 && initImage ? (canvas.width - (img.width * settings.scale)) / 2 : settings.x;
                settings.y = settings.y == 0 && initImage ? (canvas.height - (img.height * settings.scale)) / 2 : settings.y;
                context.globalCompositeOperation = 'source-atop';
                context.drawImage(img, settings.x, settings.y, img.width * settings.scale, img.height * settings.scale);
                initImage = false;
            };
        }

        // change the draggable image
        container.loadImage = function(imageUrl) {
             console.log("load");
            //if (img)
               // img.remove();
            // reset the code.
            settings.y = startY;
            settings.x = startX;
            prevX = prevY = 0;
            settings.imageUrl = imageUrl;
            initImage = true;
            container.updateStyle().then(renderInnerImage);
        };

        // change the masked Image
         container.loadMaskImage = function(imageUrl, from) {
            canvas = document.createElement("canvas");
            context = canvas.getContext('2d');
            canvas.setAttribute("draggable", "true");
            canvas.setAttribute("id", settings.id);
            settings.maskImageUrl = imageUrl;
            div = $("<div/>", {
                "class": "masked-img"
            }).append(canvas);

            // div.find("canvas").on('touchstart mousedown', function(event)
            div.find("canvas").on('dragstart', function(event) {
                if (event.handled === false) return;
                event.handled = true;
                container.onDragStart(event);
            });

            div.find("canvas").on('touchend mouseup', function(event) {
                if (event.handled === false) return;
                event.handled = true;
                container.selected(event);
            });

            div.find("canvas").bind("dragover", container.onDragOver);
            container.append(div);
            if (settings.onMaskImageCreate)
                settings.onMaskImageCreate(div);
            container.loadImage(settings.imageUrl);
        };
        container.loadMaskImage(settings.maskImageUrl);
        JQmasks.push({
            item: container,
            id: settings.id
        })
        return container;
    };
}(jQuery));

.temp {}

.container {
 background: gold;
  position: relative;
 
}

.container img {
   position:absolute;
   top:0;
   bottom:250px;
   left:0;
   right:0;
   margin:auto;
   z-index:999;
}

.masked-img {
 overflow: hidden; 
 position: relative;
}

.txtContainer{ position:absolute;  text-align:center; color:#FFF}

.pip {
  display: inline-block;
  margin: 10px 10px 0 0;
}
.remove {
  display: block;
  background: #444;
  border: 1px solid black;
  color: white;
  text-align: center;
  cursor: pointer;
}
.remove:hover {
  background: white;
  color: black;
}

<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>

<input id="fileup" name="fileup" type="file" style="display:none" >

<div class="container">

</div>

如果您需要任何其他信息，请告诉我....

Answer 1

因此，首先您应该解决 2 个不同的问题：

1) 一些如何在按钮中引用您的图像。

按钮不是很智能，您需要添加一些魔法。就像您遵循您的代码一样，当您加载图像时，基本上您是在上传带有新绘图的 canvas，因此不容易确定要删除的内容。这种方法的一个问题是您很难找到要删除的图像。但是您可以在加载图像后，return canvas 中有关此图像的信息，然后将其添加到数组中。

据我所知，每个 canvas 只有一张图片，或者至少它会覆盖最后一张，所以最简单的解决方案是清理整个 canvas。首先，我们 return 包含图像的 canvas 的 id：

// change the draggable image
    container.loadImage = function(imageUrl) {
         console.log("load");
        //if (img)
           // img.remove();
        // reset the code.
        settings.y = startY;
        settings.x = startX;
        prevX = prevY = 0;
        settings.imageUrl = imageUrl;
        initImage = true;
        container.updateStyle().then(renderInnerImage);

        // Add this
        return settings.id;
    };

然后你可以把它保存在这一行：const newImageLoadedId = mask2.loadImage(URL.createObjectURL(fileup.files[0]));

此挑战的第二步基本上是将其添加为按钮的 ID（尽管这不是推荐的方式，但可以减少您对代码的修改）：

$("<br/><span id=\"" + newImageLoadedId + "\" class=\"remove\">Remove image</span>").insertAfter("#fileup");

现在您的按钮引用了您上传的图片。

2) 实际删除

这个问题比较简单，你只需要清除canvas中的图像：

$("canvas#" + id).getContext('2d').clearReact(...)

就这些了，我建议您重构并清理一下您的代码。你可以添加一些改进，比如。

如果您想将多张图片上传到 canvas，那么此方法不是删除唯一图片的最佳方法，但您的代码现在也不允许您正确执行此操作。如果你想保留多张图片，我建议你检查 this answer，所以基本上你需要将每张图片作为一个新层进行跟踪。

使用 closure 处理点击事件，而不是将 ID 保存到按钮（这使得 ID 不是唯一的，而是同时存在于按钮和 canvas 中）。使加载图像过程更加直观，例如，甚至可以使用计数器而不是时间戳。

免责声明：此解决方案不会改进您的代码库，它只是为您提供了一个可能的解决方案来解决您所遇到的问题，并且建议的解决方案只需要很少的行数尽可能。我在最后提出了一些建议，但是随着时间的推移和对 jQuery / JavaScript 的更多体验，您将以更好的方式解决这个问题。

移除上传的图片onclick文字

Remove the uploaded image onclick text

html

javascript

jquery

canvas

delete-file