DenysMedvid/pdf2htmlEX
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Code

rescaling preserves the fixed point

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This commit is contained in:
Lu Wang 2013-11-22 20:23:38 +08:00
parent dc069d2747
commit 9252089c07
2 changed files with 56 additions and 23 deletions
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3
.gitignore vendored
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@ -17,3 +17,6 @@ test/*
Testing/*
wiki/*
doc/*
/"\\"
/share/base.min.css
/share/fancy.min.css

76
share/pdf2htmlEX.js.in
View File

@ -586,11 +586,16 @@ Viewer.prototype = {
* Code credit to PDF.js
*/
var self = this;
// Firefox specific event, so that we can prevent browser from zooming
window.addEventListener('DOMMouseScroll', function(e) {
if (e.ctrlKey) {
e.preventDefault();
self.rescale(Math.pow(self.config['scale_step'], e.detail), true);
var container = self.container;
var rect = container.getBoundingClientRect();
var fixed_point = [e.clientX - rect['left'] - container.clientLeft
,e.clientY - rect['top'] - container.clientTop];
self.rescale(Math.pow(self.config['scale_step'], e.detail), true, fixed_point);
}
}, false);
@ -663,12 +668,9 @@ Viewer.prototype = {
/**
* @param{number} ratio
* @param{boolean} is_relative
* @param{Array.<number>=} preserve_pos preserve the position after rescaling
*
* TODO: offsetX/Y is by default the center of container
* TODO consider scale on offsetX/Y
* @param{Array.<number>=} fixed_point preserve the position (relative to the top-left corner of the viewer) after rescaling
*/
rescale : function (ratio, is_relative, preserve_pos) {
rescale : function (ratio, is_relative, fixed_point) {
var old_scale = this.scale;
var new_scale = old_scale;
// set new scale
@ -682,30 +684,58 @@ Viewer.prototype = {
this.scale = new_scale;
if(!preserve_pos)
preserve_pos = [0,0]
if (!fixed_point)
fixed_point = [0,0];
// Save offset of the active page
var active_page = this.pages[this.cur_page_idx];
// translate fixed_point to the coordinate system of all pages
var container = this.container;
fixed_point[0] += container.scrollLeft;
fixed_point[1] += container.scrollTop;
var active_page_ele = active_page.page;
var prev_offset = [ active_page_ele.offsetLeft, active_page_ele.offsetTop ];
// find the visible page that contains the fixed point
// if the fixed point lies between two pages (including their borders), it's contained in the first one
var pl = this.pages;
var pl_len = pl.length;
for (var i = this.first_page_idx; i < pl_len; ++i) {
var p = pl[i].page;
if (p.offsetTop + p.clientTop >= fixed_point[1])
break;
}
var fixed_point_page_idx = i - 1;
// determine the new scroll position
// each-value consists of two parts, one inside the page, which is affected by rescaling,
// the other is outside, (e.g. borders and margins), which is not affected
// if the fixed_point is above the first page, use the first page as the reference
if (fixed_point_page_idx < 0)
fixed_point_page_idx = 0;
var fp_p = pl[fixed_point_page_idx].page;
var fp_p_width = fp_p.clientWidth;
var fp_p_height = fp_p.clientHeight;
var fp_x_ref = fp_p.offsetLeft + fp_p.clientLeft;
var fp_x_inside = fixed_point[0] - fp_x_ref;
if (fp_x_inside < 0)
fp_x_inside = 0;
else if (fp_x_inside > fp_p_width)
fp_x_inside = fp_p_width;
var fp_y_ref = fp_p.offsetTop + fp_p.clientTop;
var fp_y_inside = fixed_point[1] - fp_y_ref;
if (fp_y_inside < 0)
fp_y_inside = 0;
else if (fp_y_inside > fp_p_height)
fp_y_inside = fp_p_height;
// Rescale pages
var pl = this.pages;
for (var i = 0, l = pl.length; i < l; ++i)
for (var i = 0; i < pl_len; ++i)
pl[i].rescale(new_scale);
var container = this.container;
// Correct container scroll to keep view aligned while zooming
var correction_top = active_page_ele.offsetTop - prev_offset[1];
container.scrollTop += correction_top + preserve_pos[1];
// Take the center of the view as a reference
var prev_center_x = container.clientWidth / 2 - prev_offset[0];
// Calculate the difference respect the center of the view after the zooming
var correction_left = prev_center_x * (new_scale/old_scale - 1) + active_page_ele.offsetLeft - prev_offset[0];
// Scroll the container accordingly to keep alignment to the initial reference
container.scrollLeft += correction_left + preserve_pos[0];
container.scrollLeft += fp_x_inside / old_scale * new_scale + fp_p.offsetLeft + fp_p.clientLeft - fp_x_inside - fp_x_ref;
container.scrollTop += fp_y_inside / old_scale * new_scale + fp_p.offsetTop + fp_p.clientTop - fp_y_inside - fp_y_ref;
// some pages' visibility may be toggled, wait for next render()
// renew old schedules since rescale() may be called frequently