Merge pull request #1772 from zero41120/feature/1540-cropping-with-multiple-polygons

Feature/1540 cropping with multiple polygons
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Ian Gilman 2020-02-14 10:30:31 -08:00 committed by GitHub
commit 17cabdb923
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@ -166,6 +166,41 @@ $.Drawer.prototype = {
return this;
},
/**
* This function converts the given point from to the drawer coordinate by
* multiplying it with the pixel density.
* This function does not take rotation into account, thus assuming provided
* point is at 0 degree.
* @param {OpenSeadragon.Point} point - the pixel point to convert
*/
viewportCoordToDrawerCoord: function(point) {
var vpPoint = this.viewport.pixelFromPointNoRotate(point, true);
return new $.Point(
vpPoint.x * $.pixelDensityRatio,
vpPoint.y * $.pixelDensityRatio
);
},
/**
* This function will create multiple polygon paths on the drawing context by provided polygons,
* then clip the context to the paths.
* @param {(OpenSeadragon.Point[])[]} polygons - an array of polygons. A polygon is an array of OpenSeadragon.Point
* @param {Boolean} useSketch - Whether to use the sketch canvas or not.
*/
clipWithPolygons: function (polygons, useSketch) {
if (!this.useCanvas) {
return;
}
var context = this._getContext(useSketch);
context.beginPath();
polygons.forEach(function (polygon) {
polygon.forEach(function (coord, i) {
context[i === 0 ? 'moveTo' : 'lineTo'](coord.x, coord.y);
});
});
context.clip();
},
/**
* Set the opacity of the drawer.
* @param {Number} opacity

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@ -674,6 +674,58 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
this._setScale(height / this.normHeight, immediately);
},
/**
* Sets an array of polygons to crop the TiledImage during draw tiles.
* The render function will use the default non-zero winding rule.
* @param Polygons represented in an array of point object in image coordinates.
* Example format: [
* [{x: 197, y:172}, {x: 226, y:172}, {x: 226, y:198}, {x: 197, y:198}], // First polygon
* [{x: 328, y:200}, {x: 330, y:199}, {x: 332, y:201}, {x: 329, y:202}] // Second polygon
* [{x: 321, y:201}, {x: 356, y:205}, {x: 341, y:250}] // Third polygon
* ]
*/
setCroppingPolygons: function( polygons ) {
var isXYObject = function(obj) {
return obj instanceof $.Point || (typeof obj.x === 'number' && typeof obj.y === 'number');
};
var objectToSimpleXYObject = function(objs) {
return objs.map(function(obj) {
try {
if (isXYObject(obj)) {
return { x: obj.x, y: obj.y };
} else {
throw new Error();
}
} catch(e) {
throw new Error('A Provided cropping polygon point is not supported');
}
});
};
try {
if (!$.isArray(polygons)) {
throw new Error('Provided cropping polygon is not an array');
}
this._croppingPolygons = polygons.map(function(polygon){
return objectToSimpleXYObject(polygon);
});
} catch (e) {
$.console.error('[TiledImage.setCroppingPolygons] Cropping polygon format not supported');
$.console.error(e);
this._croppingPolygons = null;
}
},
/**
* Resets the cropping polygons, thus next render will remove all cropping
* polygon effects.
*/
resetCroppingPolygons: function() {
this._croppingPolygons = null;
},
/**
* Positions and scales the TiledImage to fit in the specified bounds.
* Note: this method fires OpenSeadragon.TiledImage.event:bounds-change
@ -1932,6 +1984,28 @@ function drawTiles( tiledImage, lastDrawn ) {
usedClip = true;
}
if (tiledImage._croppingPolygons) {
tiledImage._drawer.saveContext(useSketch);
try {
var polygons = tiledImage._croppingPolygons.map(function (polygon) {
return polygon.map(function (coord) {
var point = tiledImage
.imageToViewportCoordinates(coord.x, coord.y, true)
.rotate(-tiledImage.getRotation(true), tiledImage._getRotationPoint(true));
var clipPoint = tiledImage._drawer.viewportCoordToDrawerCoord(point);
if (sketchScale) {
clipPoint = clipPoint.times(sketchScale);
}
return clipPoint;
});
});
tiledImage._drawer.clipWithPolygons(polygons, useSketch);
} catch (e) {
$.console.error(e);
}
usedClip = true;
}
if ( tiledImage.placeholderFillStyle && tiledImage._hasOpaqueTile === false ) {
var placeholderRect = tiledImage._drawer.viewportToDrawerRectangle(tiledImage.getBounds(true));
if (sketchScale) {

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@ -0,0 +1,165 @@
<!DOCTYPE html>
<html>
<head>
<title>OpenSeadragon Cropping PolygonList Demo</title>
<script type="text/javascript" src='../../build/openseadragon/openseadragon.js'></script>
<script type="text/javascript" src='../lib/jquery-1.9.1.min.js'></script>
<style type="text/css">
.openseadragon1 {
width: 800px;
height: 600px;
background: lightgreen;
}
textarea {
width: 215px;
height: 200px;
}
.box-with-title {
padding-top: 1em;
display: inline-block;
text-align: center;
}
.buttons {
width: 215px;
}
*:focus {
outline: none;
}
</style>
</head>
<body>
<h3>
Simple demo page to show cropping with polygonList in a OpenSeadragon viewer.
</h3>
<div id="contentDiv" class="openseadragon1"></div>
<span>Click on Viewer to save polygon points</span>
<div>
<button id='resetBtn'>Reset</button>
<button id='exampleBtn'>Load Example</button>
</div>
<div class='box-with-title'>
<div class="buttons">
<button id="addPointBtn">Add Points as Polygon</button>
<button onclick="emptyElement('polygonPointEl')">Clear</button>
</div>
<textarea id="polygonPointEl"></textarea>
</div>
<div class='box-with-title'>
<div class="buttons">
<button id="cropBtn">Crop With Polygon</button>
<button onclick="emptyElement('previewEl')">Clear</button>
</div>
<textarea id='previewEl'></textarea>
</div>
<!-- Setup Viewer -->
<script type="text/javascript">
var viewer = OpenSeadragon({
// debugMode: true,
id: "contentDiv",
prefixUrl: "../../build/openseadragon/images/",
tileSources: "../data/testpattern.dzi",
showNavigator: false,
gestureSettingsMouse: {
clickToZoom: false
}
});
</script>
<script>
// Global Variables
var previewEl = document.getElementById('previewEl');
var polygonPointEl = document.getElementById('polygonPointEl');
var examples = [
[{x: 480, y: 300},{x: 300, y: 420},{x: 600, y: 420}], // Triangle
[{x: 300, y: 550},{x: 300, y: 750},{x: 600, y: 750},{x: 600, y: 550}] // Rectangle
];
// Load default examples
function loadExample(){
previewEl.value = JSON.stringify(examples);
}
loadExample();
// Set a given element's value to empty string
function emptyElement(elementId) {
document.getElementById(elementId).value = '';
}
// JSON parse a given object, then insert object assuming parsed value is array.
function insertObjectToElement(object, element) {
var parsed = []; // Default to empty array
try {
parsed = JSON.parse(element.value);
} catch(error) { }
parsed.push(object);
element.value = JSON.stringify(parsed)
}
// Add click handler to clicked point tracker
viewer.addHandler('canvas-click', function(event) {
var viewportPoint = viewer.viewport.pointFromPixel(event.position);
var p = viewer.viewport.viewportToImageCoordinates(viewportPoint);
p.x = Math.round((p.x + Number.EPSILON) * 100) / 100
p.y = Math.round((p.y + Number.EPSILON) * 100) / 100
insertObjectToElement({x:p.x, y:p.y}, polygonPointEl);
});
// Evaluate give element in JavaScript variable, default to empty array.
function readElementValueDefaultToEmptyArray(elementId) {
try {
var val = document.getElementById(elementId).value;
if (val === '') { return []; }
return eval(val); // If using JSON.parse, user must put quotes [{"x": 123, "y":12}]
} catch (e) {
return [];
}
}
// Insert value from given element into preview element
function insertValueFromElementToPreviewElement(element) {
try {
if (element.value === '') { return; }
var polygon = eval(element.value);
var polygonList = readElementValueDefaultToEmptyArray('previewEl');
polygonList.push(polygon);
element.value = '';
previewEl.value = JSON.stringify(polygonList);
} catch(error) {
console.log(error);
}
}
// Add clicked points to polygon tracker variable as point objects
document.getElementById('addPointBtn').onclick = function(){
insertValueFromElementToPreviewElement(polygonPointEl);
};
// Crop image with value in the preview element
document.getElementById('cropBtn').onclick = function(){
var polygonList = eval(previewEl.value);
var tiledImage = viewer.world.getItemAt(0);
tiledImage.setCroppingPolygons(polygonList);
viewer.forceRedraw();
emptyElement('previewEl');
};
document.getElementById('resetBtn').onclick = function(){
emptyElement('polygonPointEl');
emptyElement('previewEl');
var tiledImage = viewer.world.getItemAt(0);
tiledImage.resetCroppingPolygons();
viewer.forceRedraw();
};
document.getElementById('exampleBtn').onclick = loadExample;
</script>
</body>
</html>