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TiddlyWiki5/core/modules/macros/zoomer.js
Jeremy Ruston 04e91245cb Refactored macro mechanism
Now there is now longer a dummy DOM element corresponding to the macro
itself. Instead, macros must create a single element child. This allows
us to more easily fit Bootstrap's requirements for HTML layout (eg,
that problem with links in navbars not being recognised). The
refactoring isn't complete, there are still a few bugs to chase down
2012-06-09 18:36:32 +01:00

107 lines
3.6 KiB
JavaScript

/*\
title: $:/core/modules/macros/zoomer.js
type: application/javascript
module-type: macro
Zooming navigator macro
\*/
(function(){
/*jslint node: true, browser: true */
/*global $tw: false */
"use strict";
exports.info = {
name: "zoomer",
params: {
},
events: ["touchstart","touchmove","touchend"]
};
exports.startZoomer = function(x,y) {
this.inZoomer = true;
this.startX = x;
this.startY = y;
$tw.utils.addClass(document.body,"in-zoomer");
};
/*
Zoom the body element given a touch/mouse position in screen coordinates
*/
exports.hoverZoomer = function(x,y) {
// Put the transform origin at the top in the middle
document.body.style[$tw.browser.transformorigin] = "50% 0";
// Some shortcuts
this.bodyWidth = document.body.offsetWidth;
this.bodyHeight = document.body.offsetHeight;
this.windowWidth = window.innerWidth;
this.windowHeight = window.innerHeight;
// Compute the scale factor for fitting the entire page into the window. This is
// the scale factor we'll use when the touch is far to the left
this.minScale = this.windowHeight / this.bodyHeight;
if(this.minScale < 0.1) {
// Don't scale to less than 10% of original size
this.minScale = 0.1;
} else if(this.minScale > 1) {
// Nor should we scale up if the body is shorter than the window
this.minScale = 1;
}
// We divide the screen into two horizontal zones divided by the right edge of the body at maximum zoom (ie minimum scale)
this.splitPos = this.windowWidth/2 + (this.bodyWidth * this.minScale)/2;
// Compute the 0->1 ratio (from right to left) of the position of the touch within the right zone
this.xFactor = (this.windowWidth - x) / (this.windowWidth - this.splitPos);
if(this.xFactor > 1) {
this.xFactor = 1;
}
// And the 0->1 ratio (from top to bottom) of the position of the touch down the screen
this.yFactor = y/this.windowHeight;
// Now interpolate the scale
this.scale = (this.minScale - 1) * this.xFactor + 1;
// Apply the transform. The malarkey with .toFixed() is because otherwise we might get numbers in
// exponential notation (such as 5.1e-15) that are illegal in CSS
var preTranslateY = window.scrollY * this.xFactor,
scale = this.scale,
postTranslateY = ((this.windowHeight / this.scale) - this.bodyHeight) * this.yFactor * this.xFactor;
var transform = "translateY(" + preTranslateY.toFixed(8) + "px) " +
"scale(" + scale.toFixed(8) + ") " +
"translateY(" + postTranslateY.toFixed(8) + "px)";
document.body.style[$tw.browser.transform] = transform;
};
exports.stopZoomer = function() {
var newScrollY = this.yFactor * (this.bodyHeight - this.windowHeight);
this.inZoomer = false;
window.scrollTo(0,newScrollY);
document.body.style[$tw.browser.transform] = "translateY(" + newScrollY * this.xFactor + "px) " +
"scale(" + this.scale + ") " +
"translateY(" + ((this.windowHeight / this.scale) - this.bodyHeight) * this.yFactor * this.xFactor + "px)";
$tw.utils.removeClass(document.body,"in-zoomer");
document.body.style[$tw.browser.transform] = "translateY(0) scale(1) translateY(0)";
};
exports.handleEvent = function(event) {
switch(event.type) {
case "touchstart":
this.startZoomer(event.touches[0].clientX,event.touches[0].clientY);
this.hoverZoomer(event.touches[0].clientX,event.touches[0].clientY);
event.preventDefault();
return false;
case "touchmove":
this.hoverZoomer(event.touches[0].clientX,event.touches[0].clientY);
event.preventDefault();
return false;
case "touchend":
this.stopZoomer();
event.preventDefault();
return false;
}
};
exports.executeMacro = function() {
this.inZoomer = false;
return $tw.Tree.Element("div",{},[]);
};
})();