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집 >웹 프론트엔드 >H5 튜토리얼 >매우 멋진 HTML5 Canvas 네트워크 드로잉 보드 코드 예제에 대한 자세한 설명

매우 멋진 HTML5 Canvas 네트워크 드로잉 보드 코드 예제에 대한 자세한 설명

黄舟
黄舟원래의
2017-03-09 15:54:382173검색

굉장히 멋진 HTML5 Canvas 네트워크 드로잉보드 코드 예제에 대한 자세한 설명

오늘의 HTML 튜토리얼에서는 HTML5 Canvas를 사용하여 매우 멋지고 간단한 코드를 구현하는 방법을 알아보겠습니다. 네트워크 드로잉 보드 기능. 이 튜토리얼에서는 브러시의 종류, 브러시의 크기, 브러시의 색상을 선택할 수 있습니다. 물론 드로잉 보드로서 많은 기능이 필요합니다. 직사각형, 타원 등 복잡한 요소를 직접 구현해 보세요.

매우 멋진 HTML5 Canvas 네트워크 드로잉 보드 코드 예제에 대한 자세한 설명

여기에서 DEMO 데모도 볼 수 있습니다

이 HTML5 웹 페이지 드로잉 보드를 구현하는 원리와 원리를 간략하게 분석해 보겠습니다. 코드, 코드는 HTML과 Javascript로 구성되며 주로 Javascript 코드입니다.

HTML 코드: 

<p style="width:530px;margin:10px auto">
    <p id="canvasp"></p>
</p>

HTML 코드는 매우 간단하며 캔버스 컨테이너를 구성하고 여기에 아트보드가 생성됩니다.

Javascript 코드:

먼저 변수 세트를 통해 아트보드의 스타일을 정의하고 일부 데이터를 초기화합니다. 

var canvas;
var context;
var canvasWidth = 490;
var canvasHeight = 220;
var padding = 25;
var lineWidth = 8;
var colorPurple = "#cb3594";
var colorGreen = "#659b41";
var colorYellow = "#ffcf33";
var colorBrown = "#986928";
var outlineImage = new Image();
var crayonImage = new Image();
var markerImage = new Image();
var eraserImage = new Image();
var crayonBackgroundImage = new Image();
var markerBackgroundImage = new Image();
var eraserBackgroundImage = new Image();
var crayonTextureImage = new Image();
var clickX = new Array();
var clickY = new Array();
var clickColor = new Array();
var clickTool = new Array();
var clickSize = new Array();
var clickDrag = new Array();
var paint = false;
var curColor = colorPurple;
var curTool = "crayon";
var curSize = "normal";
var mediumStartX = 18;
var mediumStartY = 19;
var mediumImageWidth = 93;
var mediumImageHeight = 46;
var drawingAreaX = 111;
var drawingAreaY = 11;
var drawingAreaWidth = 267;
var drawingAreaHeight = 200;
var toolHotspotStartY = 23;
var toolHotspotHeight = 38;
var sizeHotspotStartY = 157;
var sizeHotspotHeight = 36;
var sizeHotspotWidthObject = new Object();
sizeHotspotWidthObject.huge = 39;
sizeHotspotWidthObject.large = 25;
sizeHotspotWidthObject.normal = 18;
sizeHotspotWidthObject.small = 16;
var totalLoadResources = 8;
var curLoadResNum = 0;

다음으로 캔버스 준비를 시작합니다. 캔버스 객체 초기화: 

function prepareCanvas()
{
    // Create the canvas (Neccessary for IE because it doesn&#39;t know what a canvas element is)
    var canvasp = document.getElementById(&#39;canvasp&#39;);
    canvas = document.createElement(&#39;canvas&#39;);
    canvas.setAttribute(&#39;width&#39;, canvasWidth);
    canvas.setAttribute(&#39;height&#39;, canvasHeight);
    canvas.setAttribute(&#39;id&#39;, &#39;canvas&#39;);
    canvasp.appendChild(canvas);
    if(typeof G_vmlCanvasManager != &#39;undefined&#39;) {
        canvas = G_vmlCanvasManager.initElement(canvas);
    }
    context = canvas.getContext("2d"); // Grab the 2d canvas context
    // Note: The above code is a workaround for IE 8 and lower. Otherwise we could have used:
    //     context = document.getElementById(&#39;canvas&#39;).getContext("2d");

    // Load images
    // -----------
    crayonImage.onload = function() { resourceLoaded(); 
    };
    crayonImage.src = "images/crayon-outline.png";
    //context.drawImage(crayonImage, 0, 0, 100, 100);

    markerImage.onload = function() { resourceLoaded(); 
    };
    markerImage.src = "images/marker-outline.png";

    eraserImage.onload = function() { resourceLoaded(); 
    };
    eraserImage.src = "images/eraser-outline.png";    

    crayonBackgroundImage.onload = function() { resourceLoaded(); 
    };
    crayonBackgroundImage.src = "images/crayon-background.png";

    markerBackgroundImage.onload = function() { resourceLoaded(); 
    };
    markerBackgroundImage.src = "images/marker-background.png";

    eraserBackgroundImage.onload = function() { resourceLoaded(); 
    };
    eraserBackgroundImage.src = "images/eraser-background.png";

    crayonTextureImage.onload = function() { resourceLoaded(); 
    };
    crayonTextureImage.src = "images/crayon-texture.png";

    outlineImage.onload = function() { resourceLoaded(); 
    };
    outlineImage.src = "images/watermelon-duck-outline.png";

    // Add mouse events
    // ----------------
    $(&#39;#canvas&#39;).mousedown(function(e)
    {
        // Mouse down location
        var mouseX = e.pageX - this.offsetLeft;
        var mouseY = e.pageY - this.offsetTop;

        if(mouseX < drawingAreaX) // Left of the drawing area
        {
            if(mouseX > mediumStartX)
            {
                if(mouseY > mediumStartY && mouseY < mediumStartY + mediumImageHeight){
                    curColor = colorPurple;
                }else if(mouseY > mediumStartY + mediumImageHeight && mouseY < mediumStartY + mediumImageHeight * 2){
                    curColor = colorGreen;
                }else if(mouseY > mediumStartY + mediumImageHeight * 2 && mouseY < mediumStartY + mediumImageHeight * 3){
                    curColor = colorYellow;
                }else if(mouseY > mediumStartY + mediumImageHeight * 3 && mouseY < mediumStartY + mediumImageHeight * 4){
                    curColor = colorBrown;
                }
            }
        }
        else if(mouseX > drawingAreaX + drawingAreaWidth) // Right of the drawing area
        {
            if(mouseY > toolHotspotStartY)
            {
                if(mouseY > sizeHotspotStartY)
                {
                    var sizeHotspotStartX = drawingAreaX + drawingAreaWidth;
                    if(mouseY < sizeHotspotStartY + sizeHotspotHeight && mouseX > sizeHotspotStartX)
                    {
                        if(mouseX < sizeHotspotStartX + sizeHotspotWidthObject.huge){
                            curSize = "huge";
                        }else if(mouseX < sizeHotspotStartX + sizeHotspotWidthObject.large + sizeHotspotWidthObject.huge){
                            curSize = "large";
                        }else if(mouseX < sizeHotspotStartX + sizeHotspotWidthObject.normal + 
                        sizeHotspotWidthObject.large + sizeHotspotWidthObject.huge){
                            curSize = "normal";
                        }else if(mouseX < sizeHotspotStartX + sizeHotspotWidthObject.small + 
                        sizeHotspotWidthObject.normal + sizeHotspotWidthObject.large + sizeHotspotWidthObject.huge){
                            curSize = "small";                        
                        }
                    }
                }
                else
                {
                    if(mouseY < toolHotspotStartY + toolHotspotHeight){
                        curTool = "crayon";
                    }else if(mouseY < toolHotspotStartY + toolHotspotHeight * 2){
                        curTool = "marker";
                    }else if(mouseY < toolHotspotStartY + toolHotspotHeight * 3){
                        curTool = "eraser";
                    }
                }
            }
        }
        else if(mouseY > drawingAreaY && mouseY < drawingAreaY + drawingAreaHeight)
        {
            // Mouse click location on drawing area
        }
        paint = true;
        addClick(mouseX, mouseY, false);
        redraw();
    });

    $(&#39;#canvas&#39;).mousemove(function(e){
        if(paint==true){
            addClick(e.pageX - this.offsetLeft, e.pageY - this.offsetTop, true);
            redraw();
        }
    });

    $(&#39;#canvas&#39;).mouseup(function(e){
        paint = false;
          redraw();
    });

    $(&#39;#canvas&#39;).mouseleave(function(e){
        paint = false;
    });
}

앞면은 주로 캔버스의 배경 이미지를 초기화하는 것이고 뒷면은 click, mouseup, mouseleave 등과 같은 브러시 이벤트를 초기화하는 것입니다. 마우스 이벤트.

주요 그리기 방법은 다음과 같습니다. 

function redraw()
{
    // Make sure required resources are loaded before redrawing
    if(curLoadResNum < totalLoadResources){ return; }

    clearCanvas();

    var locX;
    var locY;
    if(curTool == "crayon")
    {
        // Draw the crayon tool background
        context.drawImage(crayonBackgroundImage, 0, 0, canvasWidth, canvasHeight);

        // Purple
        locX = (curColor == colorPurple) ? 18 : 52;
        locY = 19;

        context.beginPath();
        context.moveTo(locX + 41, locY + 11);
        context.lineTo(locX + 41, locY + 35);
        context.lineTo(locX + 29, locY + 35);
        context.lineTo(locX + 29, locY + 33);
        context.lineTo(locX + 11, locY + 27);
        context.lineTo(locX + 11, locY + 19);
        context.lineTo(locX + 29, locY + 13);
        context.lineTo(locX + 29, locY + 11);
        context.lineTo(locX + 41, locY + 11);
        context.closePath();
        context.fillStyle = colorPurple;
        context.fill();    

        if(curColor == colorPurple){
            context.drawImage(crayonImage, locX, locY, mediumImageWidth, mediumImageHeight);
        }else{
            context.drawImage(crayonImage, 0, 0, 59, mediumImageHeight, locX, locY, 59, mediumImageHeight);
        }

        // Green
        locX = (curColor == colorGreen) ? 18 : 52;
        locY += 46;

        context.beginPath();
        context.moveTo(locX + 41, locY + 11);
        context.lineTo(locX + 41, locY + 35);
        context.lineTo(locX + 29, locY + 35);
        context.lineTo(locX + 29, locY + 33);
        context.lineTo(locX + 11, locY + 27);
        context.lineTo(locX + 11, locY + 19);
        context.lineTo(locX + 29, locY + 13);
        context.lineTo(locX + 29, locY + 11);
        context.lineTo(locX + 41, locY + 11);
        context.closePath();
        context.fillStyle = colorGreen;
        context.fill();    

        if(curColor == colorGreen){
            context.drawImage(crayonImage, locX, locY, mediumImageWidth, mediumImageHeight);
        }else{
            context.drawImage(crayonImage, 0, 0, 59, mediumImageHeight, locX, locY, 59, mediumImageHeight);
        }

        // Yellow
        locX = (curColor == colorYellow) ? 18 : 52;
        locY += 46;

        context.beginPath();
        context.moveTo(locX + 41, locY + 11);
        context.lineTo(locX + 41, locY + 35);
        context.lineTo(locX + 29, locY + 35);
        context.lineTo(locX + 29, locY + 33);
        context.lineTo(locX + 11, locY + 27);
        context.lineTo(locX + 11, locY + 19);
        context.lineTo(locX + 29, locY + 13);
        context.lineTo(locX + 29, locY + 11);
        context.lineTo(locX + 41, locY + 11);
        context.closePath();
        context.fillStyle = colorYellow;
        context.fill();    

        if(curColor == colorYellow){
            context.drawImage(crayonImage, locX, locY, mediumImageWidth, mediumImageHeight);
        }else{
            context.drawImage(crayonImage, 0, 0, 59, mediumImageHeight, locX, locY, 59, mediumImageHeight);
        }

        // Yellow
        locX = (curColor == colorBrown) ? 18 : 52;
        locY += 46;

        context.beginPath();
        context.moveTo(locX + 41, locY + 11);
        context.lineTo(locX + 41, locY + 35);
        context.lineTo(locX + 29, locY + 35);
        context.lineTo(locX + 29, locY + 33);
        context.lineTo(locX + 11, locY + 27);
        context.lineTo(locX + 11, locY + 19);
        context.lineTo(locX + 29, locY + 13);
        context.lineTo(locX + 29, locY + 11);
        context.lineTo(locX + 41, locY + 11);
        context.closePath();
        context.fillStyle = colorBrown;
        context.fill();    

        if(curColor == colorBrown){
            context.drawImage(crayonImage, locX, locY, mediumImageWidth, mediumImageHeight);
        }else{
            context.drawImage(crayonImage, 0, 0, 59, mediumImageHeight, locX, locY, 59, mediumImageHeight);
        }
    }
    else if(curTool == "marker")
    {
        // Draw the marker tool background
        context.drawImage(markerBackgroundImage, 0, 0, canvasWidth, canvasHeight);

        // Purple
        locX = (curColor == colorPurple) ? 18 : 52;
        locY = 19;

        context.beginPath();
        context.moveTo(locX + 10, locY + 24);
        context.lineTo(locX + 10, locY + 24);
        context.lineTo(locX + 22, locY + 16);
        context.lineTo(locX + 22, locY + 31);
        context.closePath();
        context.fillStyle = colorPurple;
        context.fill();    

        if(curColor == colorPurple){
            context.drawImage(markerImage, locX, locY, mediumImageWidth, mediumImageHeight);
        }else{
            context.drawImage(markerImage, 0, 0, 59, mediumImageHeight, locX, locY, 59, mediumImageHeight);
        }

        // Green
        locX = (curColor == colorGreen) ? 18 : 52;
        locY += 46;

        context.beginPath();
        context.moveTo(locX + 10, locY + 24);
        context.lineTo(locX + 10, locY + 24);
        context.lineTo(locX + 22, locY + 16);
        context.lineTo(locX + 22, locY + 31);
        context.closePath();
        context.fillStyle = colorGreen;
        context.fill();    

        if(curColor == colorGreen){
            context.drawImage(markerImage, locX, locY, mediumImageWidth, mediumImageHeight);
        }else{
            context.drawImage(markerImage, 0, 0, 59, mediumImageHeight, locX, locY, 59, mediumImageHeight);
        }

        // Yellow
        locX = (curColor == colorYellow) ? 18 : 52;
        locY += 46;

        context.beginPath();
        context.moveTo(locX + 10, locY + 24);
        context.lineTo(locX + 10, locY + 24);
        context.lineTo(locX + 22, locY + 16);
        context.lineTo(locX + 22, locY + 31);
        context.closePath();
        context.fillStyle = colorYellow;
        context.fill();    

        if(curColor == colorYellow){
            context.drawImage(markerImage, locX, locY, mediumImageWidth, mediumImageHeight);
        }else{
            context.drawImage(markerImage, 0, 0, 59, mediumImageHeight, locX, locY, 59, mediumImageHeight);
        }

        // Yellow
        locX = (curColor == colorBrown) ? 18 : 52;
        locY += 46;

        context.beginPath();
        context.moveTo(locX + 10, locY + 24);
        context.lineTo(locX + 10, locY + 24);
        context.lineTo(locX + 22, locY + 16);
        context.lineTo(locX + 22, locY + 31);
        context.closePath();
        context.fillStyle = colorBrown;
        context.fill();    

        if(curColor == colorBrown){
            context.drawImage(markerImage, locX, locY, mediumImageWidth, mediumImageHeight);
        }else{
            context.drawImage(markerImage, 0, 0, 59, mediumImageHeight, locX, locY, 59, mediumImageHeight);
        }
    }
    else if(curTool == "eraser")
    {
        context.drawImage(eraserBackgroundImage, 0, 0, canvasWidth, canvasHeight);
        context.drawImage(eraserImage, 18, 19, mediumImageWidth, mediumImageHeight);    
    }else{
        alert("Error: Current Tool is undefined");
    }

    if(curSize == "small"){
        locX = 467;
    }else if(curSize == "normal"){
        locX = 450;
    }else if(curSize == "large"){
        locX = 428;
    }else if(curSize == "huge"){
        locX = 399;
    }
    locY = 189;
    context.beginPath();
    context.rect(locX, locY, 2, 12);
    context.closePath();
    context.fillStyle = &#39;#333333&#39;;
    context.fill();    

    // Keep the drawing in the drawing area
    context.save();
    context.beginPath();
    context.rect(drawingAreaX, drawingAreaY, drawingAreaWidth, drawingAreaHeight);
    context.clip();

    var radius;
    var i = 0;
    for(; i < clickX.length; i++)
    {        
        if(clickSize[i] == "small"){
            radius = 2;
        }else if(clickSize[i] == "normal"){
            radius = 5;
        }else if(clickSize[i] == "large"){
            radius = 10;
        }else if(clickSize[i] == "huge"){
            radius = 20;
        }else{
            alert("Error: Radius is zero for click " + i);
            radius = 0;    
        }

        context.beginPath();
        if(clickDrag[i] && i){
            context.moveTo(clickX[i-1], clickY[i-1]);
        }else{
            context.moveTo(clickX[i], clickY[i]);
        }
        context.lineTo(clickX[i], clickY[i]);
        context.closePath();

        if(clickTool[i] == "eraser"){
            //context.globalCompositeOperation = "destination-out"; // To erase instead of draw over with white
            context.strokeStyle = &#39;white&#39;;
        }else{
            //context.globalCompositeOperation = "source-over";    // To erase instead of draw over with white
            context.strokeStyle = clickColor[i];
        }
        context.lineJoin = "round";
        context.lineWidth = radius;
        context.stroke();

    }
    //context.globalCompositeOperation = "source-over";// To erase instead of draw over with white
    context.restore();

    // Overlay a crayon texture (if the current tool is crayon)
    if(curTool == "crayon"){
        context.globalAlpha = 0.4; // No IE support
        context.drawImage(crayonTextureImage, 0, 0, canvasWidth, canvasHeight);
    }
    context.globalAlpha = 1; // No IE support

    // Draw the outline image
    context.drawImage(outlineImage, drawingAreaX, drawingAreaY, drawingAreaWidth, drawingAreaHeight);
}

사실 HTML5는 여전히 자바스크립트 지원이 많이 필요한데, Canvas는 매우 좋고 그 위에서 자유롭게 그래픽과 애니메이션을 그릴 수 있게 해줍니다. . HTML5 Canvas 기반의 웹 드로잉보드가 좋은 예입니다. 소스코드 다운로드>







위 내용은 매우 멋진 HTML5 Canvas 네트워크 드로잉 보드 코드 예제에 대한 자세한 설명의 상세 내용입니다. 자세한 내용은 PHP 중국어 웹사이트의 기타 관련 기사를 참조하세요!

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이전 기사：ECharts - 상세한 그래픽과 텍스트가 포함된 HTML5 Canvas 기반 JavaScript 차트 라이브러리다음 기사：ECharts - 상세한 그래픽과 텍스트가 포함된 HTML5 Canvas 기반 JavaScript 차트 라이브러리

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