Div scroll on mouse drag event javascript

up vote
-2
down vote

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hi im trying to scroll the div with mouse drag event with canvas
selection area but unable to do it properly.That div contains an image
and im drawing a canvas selection with mouseup/move/down events on
image. wanted to select the area with drag with autoscroll of div.
Somehow ive managed to scroll the div with drag but on next selection
the div is getting scroll with wrong position.

    <!DOCTYPE HTML>

<html>

<head>

<style>

body {

    margin: 0px;

    padding: 0px;

}

</style>

</head>

<body>

    <div id="outerContainer"

        style="width: 600px; height: 400px; overflow: scroll; border: thick; border-style: solid;">

        <canvas id="myCanvas" width="1700" height="2200"></canvas>

    </div>

    <script>

        var canvas = document.getElementById('myCanvas');

        var ctx = canvas.getContext('2d');

        var imageObj = new Image();



        imageObj.onload = function() {

            ctx.drawImage(imageObj, 0, 0);

        };

        imageObj.src = 'image4.jpg';

        rect = {}, drag = false;

        var xScroll;

        var yScroll;

        function init() {

            canvas.addEventListener('mousedown', mouseDown, false);

            canvas.addEventListener('mouseup', mouseUp, false);

            canvas.addEventListener('mousemove', mouseMove, false);

        }

        function clearDraw() {

            const ctx = canvas.getContext('2d');

            ctx.save();

            ctx.globalCompositeOperation = 'copy';

            ctx.strokeStyle = 'transparent';

            ctx.beginPath();

            ctx.lineTo(0, 0);

            ctx.stroke();

            ctx.restore();

        }

        function clearDrawUpdated() {

            const ctx = canvas.getContext('2d');

            ctx.save();

            ctx.setTransform(1, 0, 0, 1, 0, 0);

            ctx.clearRect(rect.startX, rect.startY, rect.w, rect.h);

        }

        function mouseDown(e) {

            rect = {};

            yScroll = document.getElementById("outerContainer").scrollTop;

            xScroll = document.getElementById("outerContainer").scrollLeft;

            rect.startX = e.pageX - this.offsetLeft + xScroll;

            rect.startY = e.pageY - this.offsetTop + yScroll;

            console.log("down:: => e.pageX: " + e.pageX + ": this.offsetLeft: "

                    + this.offsetLeft);

            drag = true;

        }

        function mouseUp() {

            document.getElementById("x1").value = rect.startX;

            document.getElementById("y1").value = rect.startY;

            document.getElementById("x2").value = rect.startX + rect.w;

            document.getElementById("y2").value = rect.startY + rect.h;

            document.getElementById("height1").value = rect.w;

            document.getElementById("width1").value = rect.h;

            drag = false;



            if (rect.w == null) {

                console.log('no area selected');

            }

            console.log("up: => " + rect.startX + ":" + rect.startY + ":"

                    + rect.w + ":" + rect.h);



        }

        function mouseMove(e) {

            if (drag) {

                rect.w = (e.pageX - this.offsetLeft + xScroll) - rect.startX;

                rect.h = (e.pageY - this.offsetTop + yScroll) - rect.startY;

                ctx.drawImage(imageObj, 0, 0);

                draw();

            }



        }

        function draw() {

            ctx.setLineDash([ 6 ])

            ctx.strokeRect(rect.startX, rect.startY, rect.w, rect.h)

        }

        init();

    </script>

    <div style="margin-left: 780px; margin-top: -286px;">

        <input name="x1" id="x1">X1</input></br> <input name="y1" id="y1">Y1</input></br>

        <input name="x2" id="x2">X2</input></br> <input name="y2" id="y2">Y2</input></br>

        <input name="height1" id="height1">H</input></br> <input name="width1"

            id="width1">W</input>

    </div>



</body>

</html>

edited Nov 19 at 8:40

asked Nov 11 at 23:16

user1495298

657

add a comment |

up vote
-2
down vote

favorite

hi im trying to scroll the div with mouse drag event with canvas
selection area but unable to do it properly.That div contains an image
and im drawing a canvas selection with mouseup/move/down events on
image. wanted to select the area with drag with autoscroll of div.
Somehow ive managed to scroll the div with drag but on next selection
the div is getting scroll with wrong position.

    <!DOCTYPE HTML>

<html>

<head>

<style>

body {

    margin: 0px;

    padding: 0px;

}

</style>

</head>

<body>

    <div id="outerContainer"

        style="width: 600px; height: 400px; overflow: scroll; border: thick; border-style: solid;">

        <canvas id="myCanvas" width="1700" height="2200"></canvas>

    </div>

    <script>

        var canvas = document.getElementById('myCanvas');

        var ctx = canvas.getContext('2d');

        var imageObj = new Image();



        imageObj.onload = function() {

            ctx.drawImage(imageObj, 0, 0);

        };

        imageObj.src = 'image4.jpg';

        rect = {}, drag = false;

        var xScroll;

        var yScroll;

        function init() {

            canvas.addEventListener('mousedown', mouseDown, false);

            canvas.addEventListener('mouseup', mouseUp, false);

            canvas.addEventListener('mousemove', mouseMove, false);

        }

        function clearDraw() {

            const ctx = canvas.getContext('2d');

            ctx.save();

            ctx.globalCompositeOperation = 'copy';

            ctx.strokeStyle = 'transparent';

            ctx.beginPath();

            ctx.lineTo(0, 0);

            ctx.stroke();

            ctx.restore();

        }

        function clearDrawUpdated() {

            const ctx = canvas.getContext('2d');

            ctx.save();

            ctx.setTransform(1, 0, 0, 1, 0, 0);

            ctx.clearRect(rect.startX, rect.startY, rect.w, rect.h);

        }

        function mouseDown(e) {

            rect = {};

            yScroll = document.getElementById("outerContainer").scrollTop;

            xScroll = document.getElementById("outerContainer").scrollLeft;

            rect.startX = e.pageX - this.offsetLeft + xScroll;

            rect.startY = e.pageY - this.offsetTop + yScroll;

            console.log("down:: => e.pageX: " + e.pageX + ": this.offsetLeft: "

                    + this.offsetLeft);

            drag = true;

        }

        function mouseUp() {

            document.getElementById("x1").value = rect.startX;

            document.getElementById("y1").value = rect.startY;

            document.getElementById("x2").value = rect.startX + rect.w;

            document.getElementById("y2").value = rect.startY + rect.h;

            document.getElementById("height1").value = rect.w;

            document.getElementById("width1").value = rect.h;

            drag = false;



            if (rect.w == null) {

                console.log('no area selected');

            }

            console.log("up: => " + rect.startX + ":" + rect.startY + ":"

                    + rect.w + ":" + rect.h);



        }

        function mouseMove(e) {

            if (drag) {

                rect.w = (e.pageX - this.offsetLeft + xScroll) - rect.startX;

                rect.h = (e.pageY - this.offsetTop + yScroll) - rect.startY;

                ctx.drawImage(imageObj, 0, 0);

                draw();

            }



        }

        function draw() {

            ctx.setLineDash([ 6 ])

            ctx.strokeRect(rect.startX, rect.startY, rect.w, rect.h)

        }

        init();

    </script>

    <div style="margin-left: 780px; margin-top: -286px;">

        <input name="x1" id="x1">X1</input></br> <input name="y1" id="y1">Y1</input></br>

        <input name="x2" id="x2">X2</input></br> <input name="y2" id="y2">Y2</input></br>

        <input name="height1" id="height1">H</input></br> <input name="width1"

            id="width1">W</input>

    </div>



</body>

</html>

edited Nov 19 at 8:40

asked Nov 11 at 23:16

user1495298

657

add a comment |

up vote
-2
down vote

favorite

hi im trying to scroll the div with mouse drag event with canvas
selection area but unable to do it properly.That div contains an image
and im drawing a canvas selection with mouseup/move/down events on
image. wanted to select the area with drag with autoscroll of div.
Somehow ive managed to scroll the div with drag but on next selection
the div is getting scroll with wrong position.

    <!DOCTYPE HTML>

<html>

<head>

<style>

body {

    margin: 0px;

    padding: 0px;

}

</style>

</head>

<body>

    <div id="outerContainer"

        style="width: 600px; height: 400px; overflow: scroll; border: thick; border-style: solid;">

        <canvas id="myCanvas" width="1700" height="2200"></canvas>

    </div>

    <script>

        var canvas = document.getElementById('myCanvas');

        var ctx = canvas.getContext('2d');

        var imageObj = new Image();



        imageObj.onload = function() {

            ctx.drawImage(imageObj, 0, 0);

        };

        imageObj.src = 'image4.jpg';

        rect = {}, drag = false;

        var xScroll;

        var yScroll;

        function init() {

            canvas.addEventListener('mousedown', mouseDown, false);

            canvas.addEventListener('mouseup', mouseUp, false);

            canvas.addEventListener('mousemove', mouseMove, false);

        }

        function clearDraw() {

            const ctx = canvas.getContext('2d');

            ctx.save();

            ctx.globalCompositeOperation = 'copy';

            ctx.strokeStyle = 'transparent';

            ctx.beginPath();

            ctx.lineTo(0, 0);

            ctx.stroke();

            ctx.restore();

        }

        function clearDrawUpdated() {

            const ctx = canvas.getContext('2d');

            ctx.save();

            ctx.setTransform(1, 0, 0, 1, 0, 0);

            ctx.clearRect(rect.startX, rect.startY, rect.w, rect.h);

        }

        function mouseDown(e) {

            rect = {};

            yScroll = document.getElementById("outerContainer").scrollTop;

            xScroll = document.getElementById("outerContainer").scrollLeft;

            rect.startX = e.pageX - this.offsetLeft + xScroll;

            rect.startY = e.pageY - this.offsetTop + yScroll;

            console.log("down:: => e.pageX: " + e.pageX + ": this.offsetLeft: "

                    + this.offsetLeft);

            drag = true;

        }

        function mouseUp() {

            document.getElementById("x1").value = rect.startX;

            document.getElementById("y1").value = rect.startY;

            document.getElementById("x2").value = rect.startX + rect.w;

            document.getElementById("y2").value = rect.startY + rect.h;

            document.getElementById("height1").value = rect.w;

            document.getElementById("width1").value = rect.h;

            drag = false;



            if (rect.w == null) {

                console.log('no area selected');

            }

            console.log("up: => " + rect.startX + ":" + rect.startY + ":"

                    + rect.w + ":" + rect.h);



        }

        function mouseMove(e) {

            if (drag) {

                rect.w = (e.pageX - this.offsetLeft + xScroll) - rect.startX;

                rect.h = (e.pageY - this.offsetTop + yScroll) - rect.startY;

                ctx.drawImage(imageObj, 0, 0);

                draw();

            }



        }

        function draw() {

            ctx.setLineDash([ 6 ])

            ctx.strokeRect(rect.startX, rect.startY, rect.w, rect.h)

        }

        init();

    </script>

    <div style="margin-left: 780px; margin-top: -286px;">

        <input name="x1" id="x1">X1</input></br> <input name="y1" id="y1">Y1</input></br>

        <input name="x2" id="x2">X2</input></br> <input name="y2" id="y2">Y2</input></br>

        <input name="height1" id="height1">H</input></br> <input name="width1"

            id="width1">W</input>

    </div>



</body>

</html>

edited Nov 19 at 8:40

asked Nov 11 at 23:16

user1495298

657

hi im trying to scroll the div with mouse drag event with canvas
selection area but unable to do it properly.That div contains an image
and im drawing a canvas selection with mouseup/move/down events on
image. wanted to select the area with drag with autoscroll of div.
Somehow ive managed to scroll the div with drag but on next selection
the div is getting scroll with wrong position.

    <!DOCTYPE HTML>

<html>

<head>

<style>

body {

    margin: 0px;

    padding: 0px;

}

</style>

</head>

<body>

    <div id="outerContainer"

        style="width: 600px; height: 400px; overflow: scroll; border: thick; border-style: solid;">

        <canvas id="myCanvas" width="1700" height="2200"></canvas>

    </div>

    <script>

        var canvas = document.getElementById('myCanvas');

        var ctx = canvas.getContext('2d');

        var imageObj = new Image();



        imageObj.onload = function() {

            ctx.drawImage(imageObj, 0, 0);

        };

        imageObj.src = 'image4.jpg';

        rect = {}, drag = false;

        var xScroll;

        var yScroll;

        function init() {

            canvas.addEventListener('mousedown', mouseDown, false);

            canvas.addEventListener('mouseup', mouseUp, false);

            canvas.addEventListener('mousemove', mouseMove, false);

        }

        function clearDraw() {

            const ctx = canvas.getContext('2d');

            ctx.save();

            ctx.globalCompositeOperation = 'copy';

            ctx.strokeStyle = 'transparent';

            ctx.beginPath();

            ctx.lineTo(0, 0);

            ctx.stroke();

            ctx.restore();

        }

        function clearDrawUpdated() {

            const ctx = canvas.getContext('2d');

            ctx.save();

            ctx.setTransform(1, 0, 0, 1, 0, 0);

            ctx.clearRect(rect.startX, rect.startY, rect.w, rect.h);

        }

        function mouseDown(e) {

            rect = {};

            yScroll = document.getElementById("outerContainer").scrollTop;

            xScroll = document.getElementById("outerContainer").scrollLeft;

            rect.startX = e.pageX - this.offsetLeft + xScroll;

            rect.startY = e.pageY - this.offsetTop + yScroll;

            console.log("down:: => e.pageX: " + e.pageX + ": this.offsetLeft: "

                    + this.offsetLeft);

            drag = true;

        }

        function mouseUp() {

            document.getElementById("x1").value = rect.startX;

            document.getElementById("y1").value = rect.startY;

            document.getElementById("x2").value = rect.startX + rect.w;

            document.getElementById("y2").value = rect.startY + rect.h;

            document.getElementById("height1").value = rect.w;

            document.getElementById("width1").value = rect.h;

            drag = false;



            if (rect.w == null) {

                console.log('no area selected');

            }

            console.log("up: => " + rect.startX + ":" + rect.startY + ":"

                    + rect.w + ":" + rect.h);



        }

        function mouseMove(e) {

            if (drag) {

                rect.w = (e.pageX - this.offsetLeft + xScroll) - rect.startX;

                rect.h = (e.pageY - this.offsetTop + yScroll) - rect.startY;

                ctx.drawImage(imageObj, 0, 0);

                draw();

            }



        }

        function draw() {

            ctx.setLineDash([ 6 ])

            ctx.strokeRect(rect.startX, rect.startY, rect.w, rect.h)

        }

        init();

    </script>

    <div style="margin-left: 780px; margin-top: -286px;">

        <input name="x1" id="x1">X1</input></br> <input name="y1" id="y1">Y1</input></br>

        <input name="x2" id="x2">X2</input></br> <input name="y2" id="y2">Y2</input></br>

        <input name="height1" id="height1">H</input></br> <input name="width1"

            id="width1">W</input>

    </div>



</body>

</html>

javascript canvas mouseevent

edited Nov 19 at 8:40

asked Nov 11 at 23:16

user1495298

657

edited Nov 19 at 8:40

asked Nov 11 at 23:16

user1495298

657

edited Nov 19 at 8:40

asked Nov 11 at 23:16

user1495298

657

asked Nov 11 at 23:16

user1495298

657

asked Nov 11 at 23:16

user1495298

657

add a comment |

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