Question

我们正在使用JSON获取图像。在json中，还提到了图像的 X [左]和 Y [顶部]位置，我需要使用相同的位置。

所以我用绝对位置。如果我使用相对位置，则图像将不会显示在正确的位置，因此在这种情况下是否可以使页面响应？

如果是的话，我需要采取什么措施使其具有响应能力？

onMaskImageCreate: function(img) {
                    // Mask image positions
                    img.css({
                        "position": "absolute",
                        "left": x + "px",
                        "top": y + "px"
                    });

代码段：

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

let jsonData = {
    "layers": [{
        "x": 0,
        "height": 612,
        "layers": [{
            "x": 160,
            "src": "ax0HVTs.png",
            "y": 291,
            "height": 296,
            "width": 429,
            "name": "mask_1"
        }, {
            "x": 25,
            "src": "hEM2kEP.png",
            "height": 324,
            "width": 471,
            "y": 22,
            "name": "mask_2"
        }],
        "y": 0,
        "width": 612
    }]
};

const containerElement = $('#container');
const fileUp = $('#fileup');
let mask;

$(function() {

    // Upload image onclick mask image

    containerElement.click(function(e) {
                var res = e.target;
                target = res.id;
                if (e.target.getContext) {
                    // click only inside Non Transparent part 
                    var pixel = e.target.getContext('2d').getImageData(e.offsetX, e.offsetY, 1, 1).data;
                    if (pixel[3] === 255) {
                        setTimeout(() => {
                            $('#fileup').click();
                        }, 20);
                    }
                }
            });

    // 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,
                    height: layer.height,
                    width: layer.width,
                    name: layer.name
                });
            } else if (layer.layers) {
                let newArr = getAllSrc(layer.layers);
                if (newArr.length > 0) {
                    newArr.forEach(({
                        src,
                        x,
                        y,
                        height,
                        width,
                        name
                    }) => {
                        arr.push({
                            src,
                            x: (layer.x + x),
                            y: (layer.y + y),
                            height,
                            width,
                            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 = [];

        containerElement.css('width', width + "px").css('height', height + "px").addClass('temp');

        for (let {
                src,
                x,
                y,
                name
            } of arr) {                    
         
            var imageUrl1 = imageUrl;

            var mask = $(".container").mask({
                imageUrl: name.indexOf('mask_') !== -1 ? imageUrl1 : undefined,

                // Mask images
                maskImageUrl: 'https://i.imgur.com/' + src,
                // end

                onMaskImageCreate: function(img) {
                    // Mask image positions
                    img.css({
                        "position": "absolute",
                        "left": x + "px",
                        "top": y + "px"
                    });
                    // end
                },
                id: counter
            });           
          
            table.push(mask);
            fileup.onchange = function() {

                let mask2 = table[target];
                const newImageLoadedId = mask2.loadImage(URL.createObjectURL(fileup.files[0]));
                document.getElementById('fileup').value = "";               
            };
            counter++;
        }
        return mask;
    }

    mask = json(jsonData);
}); // end of function

// Image code

(function($) {
    window.JQmasks = [];
    $.fn.mask = function(options) {
        // This is the easiest way to have default options.
        const 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) {},
            rotate: 0,
        }, options);

        // Create the image properties
        settings.maskImage = new Image
        settings.image = new Image

        // set the cross-origin attributes
        settings.maskImage.setAttribute('crossOrigin', 'anonymous');
        settings.image.setAttribute('crossOrigin', 'anonymous');

        settings.maskImage.onload = function() {
            // once the mask is loaded, load the image
            container.loadImage(settings.imageUrl, true)
            container.drawMask()
        }

        settings.image.onload = function() {
            // once the image is loaded, render to canvas            
            container.drawImage()
        }

        var container = $(this);

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

        container.getImagePosition = function() {
            return {
                x: settings.x,
                y: settings.y,
                scale: settings.scale
            };
        };
        
        container.drawMask = function() {
            if (!settings.maskImage) return true;
            canvas.width = settings.maskImage.width;
            canvas.height = settings.maskImage.height;
            context.save();
            context.beginPath();
            context.globalCompositeOperation = "source-over";
            // draw the masked image after scaling
            if (settings.maskImage)
                context.drawImage(settings.maskImage, 0, 0, settings.maskImage.width, settings.maskImage
                    .height);
            context.restore()
        };

        container.drawImage = function() {
            const img = settings.image

            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.save();
            context.translate(settings.x + img.width / 2, settings.y + img.height / 2);
            context.rotate(settings.rotate);
            context.scale(settings.scale, settings.scale);
            context.translate(-(settings.x + img.width / 2), -(settings.y + img.height / 2));
            let width = img.width,
                height = img.height;
            if (img)
                context.drawImage(img, settings.x, settings.y, width, height);
            context.restore();
            initImage = false;            
        }

        container.loadImage = function(imageUrl, isMask) {
            if (!imageUrl) return true;
            settings.y = startY;
            settings.x = startX;
            settings.scale = 1;
            settings.rotate = 0;
            prevX = prevY = 0;
            initImage = true;
            settings.image.src = imageUrl; // CHANGED
            if (!isMask)
                container.data('image_set' + settings.id, true)
            return settings.id;
        };

        container.loadMaskImage = function(imageUrl, from) {
            console.log('loading mask image from', imageUrl, from)
            canvas = document.createElement("canvas");
            context = canvas.getContext('2d');
            canvas.setAttribute("draggable", "true");
            canvas.setAttribute("id", settings.id);
            // settings.maskImageUrl = imageUrl;
            settings.maskImage.src = imageUrl // CHANGED

            div = $("<div/>", {
                "class": "masked-img"
            }).append(canvas);

            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);            
        };

        if (settings.maskImageUrl) {
            container.loadMaskImage(settings.maskImageUrl);
        }
        JQmasks.push({
            item: container,
            id: settings.id
        })
        // Edit image
        div.addClass('masked-img' + settings.id);
        div.attr('data-id', settings.id);
        // ends
        return container;
    };
}(jQuery));

.container {
	background: silver;
	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;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input id="fileup" name="fileup" type="file" style="display:none">
<div id="container" class="container">
</div>

这里是Fiddle，Codepen，Pastebin

Answer 1

尝试动态更改“画布”宽度，然后可以使其具有响应性

带有绝对定位图像的响应页面

1 个答案: