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Added a patch to help slow down the scroll devices that fire too fast. This new code reduces the number of 'canvas-scroll' events that fire and slows down the zoom process.

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This commit is contained in:
Grant Echols 2015-10-27 14:00:45 -06:00
parent fb8e19b50d
commit 19c6179533
2 changed files with 50 additions and 32 deletions
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6
src/openseadragon.js
View File

@ -255,6 +255,11 @@
* @property {Boolean} [preserveImageSizeOnResize=false]
* Set to true to have the image size preserved when the viewer is resized. This requires autoResize=true (default).
*
* @property {Number} [minScrollDelta=3]
* Number of milliseconds between canvas-scroll events. This value helps normalize the rate of canvas-scroll
* events between different devices, causing the faster devices to slow down enough to make the zoom control
* more manageable.
*
* @property {Number} [pixelsPerWheelLine=40]
* For pixel-resolution scrolling devices, the number of pixels equal to one scroll line.
*
@ -1003,6 +1008,7 @@ if (typeof define === 'function' && define.amd) {
pixelsPerWheelLine: 40,
autoResize: true,
preserveImageSizeOnResize: false, // requires autoResize=true
minScrollDelta: 3,
//DEFAULT CONTROL SETTINGS
showSequenceControl: true, //SEQUENCE

76
src/viewer.js
View File

@ -604,7 +604,7 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
var originalSuccess = options.success;
options.success = function(event) {
successes++;
// TODO: now that options has other things besides tileSource, the overlays
// should probably be at the options level, not the tileSource level.
if (options.tileSource.overlays) {
@ -2735,42 +2735,54 @@ function onCanvasPinch( event ) {
return false;
}
var lastScroll = new Date().getTime();
function onCanvasScroll( event ) {
var gestureSettings,
factor;
factor,
thisScroll,
deltaScroll;
if ( !event.preventDefaultAction && this.viewport ) {
gestureSettings = this.gestureSettingsByDeviceType( event.pointerType );
if ( gestureSettings.scrollToZoom ) {
factor = Math.pow( this.zoomPerScroll, event.scroll );
this.viewport.zoomBy(
factor,
this.viewport.pointFromPixel( event.position, true )
);
this.viewport.applyConstraints();
/* Certain scroll devices fire the scroll event way too fast so we are injecting a simple adjustment to keep things
* partially normalized. If we have already fired an event within the last 'minScrollDelta' milliseconds we skip
* this one and wait for the next event. */
thisScroll = new Date().getTime();
deltaScroll = thisScroll - lastScroll;
if (deltaScroll > this.minScrollDelta) {
lastScroll = thisScroll;
if ( !event.preventDefaultAction && this.viewport ) {
gestureSettings = this.gestureSettingsByDeviceType( event.pointerType );
if ( gestureSettings.scrollToZoom ) {
factor = Math.pow( this.zoomPerScroll, event.scroll );
this.viewport.zoomBy(
factor,
this.viewport.pointFromPixel( event.position, true )
);
this.viewport.applyConstraints();
}
}
/**
* Raised when a scroll event occurs on the {@link OpenSeadragon.Viewer#canvas} element (mouse wheel).
*
* @event canvas-scroll
* @memberof OpenSeadragon.Viewer
* @type {object}
* @property {OpenSeadragon.Viewer} eventSource - A reference to the Viewer which raised this event.
* @property {OpenSeadragon.MouseTracker} tracker - A reference to the MouseTracker which originated this event.
* @property {OpenSeadragon.Point} position - The position of the event relative to the tracked element.
* @property {Number} scroll - The scroll delta for the event.
* @property {Boolean} shift - True if the shift key was pressed during this event.
* @property {Object} originalEvent - The original DOM event.
* @property {?Object} userData - Arbitrary subscriber-defined object.
*/
this.raiseEvent( 'canvas-scroll', {
tracker: event.eventSource,
position: event.position,
scroll: event.scroll,
shift: event.shift,
originalEvent: event.originalEvent
});
}
/**
* Raised when a scroll event occurs on the {@link OpenSeadragon.Viewer#canvas} element (mouse wheel).
*
* @event canvas-scroll
* @memberof OpenSeadragon.Viewer
* @type {object}
* @property {OpenSeadragon.Viewer} eventSource - A reference to the Viewer which raised this event.
* @property {OpenSeadragon.MouseTracker} tracker - A reference to the MouseTracker which originated this event.
* @property {OpenSeadragon.Point} position - The position of the event relative to the tracked element.
* @property {Number} scroll - The scroll delta for the event.
* @property {Boolean} shift - True if the shift key was pressed during this event.
* @property {Object} originalEvent - The original DOM event.
* @property {?Object} userData - Arbitrary subscriber-defined object.
*/
this.raiseEvent( 'canvas-scroll', {
tracker: event.eventSource,
position: event.position,
scroll: event.scroll,
shift: event.shift,
originalEvent: event.originalEvent
});
if (gestureSettings && gestureSettings.scrollToZoom) {
//cancels event