Html 以PDF格式绘制框并捕获坐标

我想用画布在pdf中画一个方框，并找出方框的坐标。我这里有一个代码，在选择pdf之后，它将转换为画布，在画布上我们创建了一个方框，但方框没有显示。 为此，请使用javascript pdf.js和pdf.worker.js

要使用此代码，请使用附加的javascript文件

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我也有同样的要求

检查此链接。我在这里为你做了演示

检查页面源代码中的JavaScript代码

如果您需要zip中的所有文件，请告诉我。 这是

下面是绘制矩形的代码。Rest是PDF.js，它已经在那里了

"use strict";
requestAnimationFrame(mainLoop);
const canvas = document.getElementById("pdf-canvas");
const ctx = canvas.getContext("2d");
const storedRects = [];
const baseImage = loadImage("");
var refresh = true;
const rect = (() => {
    var x1, y1, x2, y2;
    var show = false;
    function fix() {
        rect.x = Math.min(x1, x2);
        rect.y = Math.min(y1, y2);
        rect.w = Math.max(x1, x2) - Math.min(x1, x2);
        rect.h = Math.max(y1, y2) - Math.min(y1, y2);


         jQuery("body").click(function(e) {
            console.log(rect.x+'='+rect.y+'='+rect.w+'='+rect.h);
             $('#output').html('current x : '+rect.x+', current y : '+rect.y+', width : '+rect.w+', height : '+rect.h);

            if (e.target.id == "pdf-canvas") {
                ddrag();
                jQuery(".position_x").val(rect.x);
                jQuery(".position_y").val(rect.y);
                jQuery(".position_w").val(rect.w);
                jQuery(".position_h").val(rect.h);
            }
         });
    }
    function draw(ctx) { 
        ctx.clearRect(this.x, this.y, this.w, this.h);
        ctx.strokeRect(this.x, this.y, this.w, this.h) 
        }
    const rect = {x : 0, y : 0, w : 0, h : 0,  draw};
    const API = {
        restart(point) {
            x2 = x1 = point.x;
            y2 = y1 = point.y;
            fix();
            show = true;
        },
        update(point) {
            x2 = point.x;
            y2 = point.y;
            fix();
            show = true;
        },
        toRect() {
            show = false;
            return Object.assign({}, rect);
        },
        draw(ctx) {
            if (show) { rect.draw(ctx) }
        },
        show : false,
    }
    return API;
})();

function loadImage(url) {
    const image = new Image();
    image.src = url;
    image.onload = () => refresh = true;
    return image;
}

const mouse = {
    button : false,
    x : 0,
    y : 0,
    down : false,
    up : false,
    element : null,
    event(e) {

        const m = mouse;
        m.bounds = m.element.getBoundingClientRect();
        m.x = e.pageX - m.bounds.left - scrollX;
        m.y = e.pageY - m.bounds.top - scrollY;
        const prevButton = m.button;
        m.button = e.type === "mousedown" ? true : e.type === "mouseup" ? false : mouse.button;
        if (!prevButton && m.button) { m.down = true; 
            /*
            var cv=document.createElement('canvas'); 
            cv.width=canvas.width;
            cv.height=canvas.height;
            */
        }
        if (prevButton && !m.button) { m.up = true }
    },
    start(element) {
        mouse.element = element;
        "down,up,move".split(",").forEach(name => document.addEventListener("mouse" + name, mouse.event));
    }
}

mouse.start(canvas);
function draw() {

    const storedRects = [];
    ctx.restore();

    ctx.drawImage(baseImage, 0, 0, ctx.canvas.width, ctx.canvas.width);
    ctx.lineWidth = 1;
    ctx.strokeStyle = "yellow";
    storedRects.forEach(rect => rect.draw(ctx));
    ctx.strokeStyle = "red";
    rect.draw(ctx);
}
function mainLoop() {
    if (refresh || mouse.down || mouse.up || mouse.button) {
        refresh = false;
        if (mouse.down) {
            mouse.down = false;
            rect.restart(mouse);
        } else if (mouse.button) {
            rect.update(mouse);
        } else if (mouse.up) {
            mouse.up = false;
            rect.update(mouse);
            //storedRects.push(rect.toRect());
        }
        draw();
    }
    requestAnimationFrame(mainLoop)
}

function clearCanvas (canvas)
{
    const storedRects = [];
    //alert(jQuery(".position_x").val());
    jQuery('#pdf-contents').removeClass('test');

   // ctx.fillRect(jQuery(".position_x").val(), jQuery(".position_y").val(), jQuery(".position_w").val(),jQuery(".position_h").val());   
    //ctx.clearRect(0,0,jQuery(".position_w").val(),jQuery(".position_h").val());

    //ctx.drawImage(baseImage, 0, 0, ctx.canvas.width, ctx.canvas.width);
//      URL.createObjectURL($("#file-input").get(0).files[0]); /*reload mate*/


    //alert(URL.createObjectURL($("#file-input").get(0).files[0]))
    showPDF(URL.createObjectURL($("#file-input").get(0).files[0]));
    //setTimeout(function(){ showPDF(URL.createObjectURL($("#file-input").get(0).files[0])); }, 3000);

} 
function ddrag(){

     //const storedRects = [];
     jQuery('.test #pdf-canvas').mousedown(function(){ 
     console.log(jQuery(this).parent().parent().attr('class'));
        if(jQuery(this).parent().parent().attr('class')=="test"){
            return false;
        }else{
            return true;
        }
    });
    jQuery('#pdf-contents').addClass('test');

        //return false; 


}

---

我也有同样的要求

检查此链接。我在这里为你做了演示

检查页面源代码中的JavaScript代码

如果您需要zip中的所有文件，请告诉我。 这是

下面是绘制矩形的代码。Rest是PDF.js，它已经在那里了

"use strict";
requestAnimationFrame(mainLoop);
const canvas = document.getElementById("pdf-canvas");
const ctx = canvas.getContext("2d");
const storedRects = [];
const baseImage = loadImage("");
var refresh = true;
const rect = (() => {
    var x1, y1, x2, y2;
    var show = false;
    function fix() {
        rect.x = Math.min(x1, x2);
        rect.y = Math.min(y1, y2);
        rect.w = Math.max(x1, x2) - Math.min(x1, x2);
        rect.h = Math.max(y1, y2) - Math.min(y1, y2);


         jQuery("body").click(function(e) {
            console.log(rect.x+'='+rect.y+'='+rect.w+'='+rect.h);
             $('#output').html('current x : '+rect.x+', current y : '+rect.y+', width : '+rect.w+', height : '+rect.h);

            if (e.target.id == "pdf-canvas") {
                ddrag();
                jQuery(".position_x").val(rect.x);
                jQuery(".position_y").val(rect.y);
                jQuery(".position_w").val(rect.w);
                jQuery(".position_h").val(rect.h);
            }
         });
    }
    function draw(ctx) { 
        ctx.clearRect(this.x, this.y, this.w, this.h);
        ctx.strokeRect(this.x, this.y, this.w, this.h) 
        }
    const rect = {x : 0, y : 0, w : 0, h : 0,  draw};
    const API = {
        restart(point) {
            x2 = x1 = point.x;
            y2 = y1 = point.y;
            fix();
            show = true;
        },
        update(point) {
            x2 = point.x;
            y2 = point.y;
            fix();
            show = true;
        },
        toRect() {
            show = false;
            return Object.assign({}, rect);
        },
        draw(ctx) {
            if (show) { rect.draw(ctx) }
        },
        show : false,
    }
    return API;
})();

function loadImage(url) {
    const image = new Image();
    image.src = url;
    image.onload = () => refresh = true;
    return image;
}

const mouse = {
    button : false,
    x : 0,
    y : 0,
    down : false,
    up : false,
    element : null,
    event(e) {

        const m = mouse;
        m.bounds = m.element.getBoundingClientRect();
        m.x = e.pageX - m.bounds.left - scrollX;
        m.y = e.pageY - m.bounds.top - scrollY;
        const prevButton = m.button;
        m.button = e.type === "mousedown" ? true : e.type === "mouseup" ? false : mouse.button;
        if (!prevButton && m.button) { m.down = true; 
            /*
            var cv=document.createElement('canvas'); 
            cv.width=canvas.width;
            cv.height=canvas.height;
            */
        }
        if (prevButton && !m.button) { m.up = true }
    },
    start(element) {
        mouse.element = element;
        "down,up,move".split(",").forEach(name => document.addEventListener("mouse" + name, mouse.event));
    }
}

mouse.start(canvas);
function draw() {

    const storedRects = [];
    ctx.restore();

    ctx.drawImage(baseImage, 0, 0, ctx.canvas.width, ctx.canvas.width);
    ctx.lineWidth = 1;
    ctx.strokeStyle = "yellow";
    storedRects.forEach(rect => rect.draw(ctx));
    ctx.strokeStyle = "red";
    rect.draw(ctx);
}
function mainLoop() {
    if (refresh || mouse.down || mouse.up || mouse.button) {
        refresh = false;
        if (mouse.down) {
            mouse.down = false;
            rect.restart(mouse);
        } else if (mouse.button) {
            rect.update(mouse);
        } else if (mouse.up) {
            mouse.up = false;
            rect.update(mouse);
            //storedRects.push(rect.toRect());
        }
        draw();
    }
    requestAnimationFrame(mainLoop)
}

function clearCanvas (canvas)
{
    const storedRects = [];
    //alert(jQuery(".position_x").val());
    jQuery('#pdf-contents').removeClass('test');

   // ctx.fillRect(jQuery(".position_x").val(), jQuery(".position_y").val(), jQuery(".position_w").val(),jQuery(".position_h").val());   
    //ctx.clearRect(0,0,jQuery(".position_w").val(),jQuery(".position_h").val());

    //ctx.drawImage(baseImage, 0, 0, ctx.canvas.width, ctx.canvas.width);
//      URL.createObjectURL($("#file-input").get(0).files[0]); /*reload mate*/


    //alert(URL.createObjectURL($("#file-input").get(0).files[0]))
    showPDF(URL.createObjectURL($("#file-input").get(0).files[0]));
    //setTimeout(function(){ showPDF(URL.createObjectURL($("#file-input").get(0).files[0])); }, 3000);

} 
function ddrag(){

     //const storedRects = [];
     jQuery('.test #pdf-canvas').mousedown(function(){ 
     console.log(jQuery(this).parent().parent().attr('class'));
        if(jQuery(this).parent().parent().attr('class')=="test"){
            return false;
        }else{
            return true;
        }
    });
    jQuery('#pdf-contents').addClass('test');

        //return false; 


}

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您好@Viral，您答案中的链接不再有效。你能帮我提供你的解决方案的示例文件吗？@你能提供新的链接吗？在处理相同的要求时，您的答案中的链接不再有效。你能帮我提供你的解决方案的示例文件吗？@你能提供新的链接吗？处理相同的要求