DenysMedvid/pdf2htmlEX
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mirror of https://github.com/pdf2htmlEX/pdf2htmlEX.git synced 2024-07-03 08:38:39 +00:00
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caching of height / width; rendering optimizations while zooming

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This commit is contained in:
Michele Redolfi 2013-07-16 20:19:25 +02:00
parent 43c330f9b7
commit ea1878e233
1 changed files with 54 additions and 32 deletions
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86
share/pdf2htmlEX.js.in
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@ -20,6 +20,8 @@ var pdf2htmlEX = (function(){
};
var DEFAULT_PAGES_TO_PRELOAD = 3;
var NR_PAGES_TO_PRERENDER_ON_ZOOM = 4; // 0: disable render optimizations (less CPU usage but flickering on zoom)
var pdf2htmlEX = new Object();
var EPS = 1e-6;
@ -62,7 +64,7 @@ var pdf2htmlEX = (function(){
* set_r : last set
* cur_r : currently using
*/
this.default_r = this.set_r = this.cur_r = this.$p.height() / this.$b.height();
this.default_r = this.set_r = this.cur_r = this.h / this.$b.height();
this.data = $($('.'+CSS_CLASS_NAMES['page_data'], this.$p)[0]).data('data');
@ -79,16 +81,18 @@ var pdf2htmlEX = (function(){
this.shown = false;
},
show : function(){
if(Math.abs(this.set_r - this.cur_r) > EPS) {
this.cur_r = this.set_r;
this.$b.css('transform', 'scale('+this.cur_r.toFixed(3)+')');
}
if (! this.shown) {
this.$b.addClass('opened');
this.shown = true;
if (this.loaded) {
if(Math.abs(this.set_r - this.cur_r) > EPS) {
this.cur_r = this.set_r;
this.$b.css('transform', 'scale('+this.cur_r.toFixed(3)+')');
}
if (! this.shown) {
this.$b.addClass('opened');
this.shown = true;
}
}
},
rescale : function(ratio) {
rescale : function(ratio, keep_shown) {
if(ratio == 0) {
this.set_r = this.default_r;
} else {
@ -96,15 +100,16 @@ var pdf2htmlEX = (function(){
}
/* wait for redraw */
// this.hide();
if (! keep_shown)
this.hide();
this.$p.height(this.h * this.set_r);
this.$p.width(this.w * this.set_r);
this.$d.height(this.h * this.set_r);
this.$d.width(this.w * this.set_r);
},
/* return if any part of this page is shown in the container */
is_visible : function() {
var off = this.position();
return !((off[1] > this.height()) || (off[1] + this.$container.height() < 0));
return !((off[1] > this.h) || (off[1] + this.$container.height() < 0));
},
/* return if this page or any neighbor of it is visible */
is_nearly_visible : function() {
@ -112,18 +117,15 @@ var pdf2htmlEX = (function(){
/* I should use the height of the previous page or the next page here
* but since they are not easily available, just use '*2', which should be a good estimate in most cases
*/
return !((off[1] > this.height() * 2) || (off[1] + this.$container.height() * 2 < 0));
return !((off[1] > this.h * 2) || (off[1] + this.$container.height() * 2 < 0));
},
/* return the coordinate of the top-left corner of container
* in our cooridnate system
* in our coordinate system
*/
position : function () {
var off = this.$p.offset();
var off_c = this.$container.offset();
return [off_c.left-off.left, off_c.top-off.top];
},
height : function() {
return this.$p.height();
}
});
@ -214,6 +216,7 @@ var pdf2htmlEX = (function(){
var $new_pf = _.$container.find('#' + CSS_CLASS_NAMES['page_frame'] + page_no_hex);
_.pages[idx] = new Page($new_pf, _.$container);
_.pages[idx].hide();
_.pages[idx].rescale(_.scale);
_.schedule_render();
@ -332,11 +335,26 @@ var pdf2htmlEX = (function(){
offsetX = 0;
if (! offsetY)
offsetY = 0;
// Save offset of the active page
var active_page = this.get_active_page();
var prev_offset = active_page.$p.offset();
var old_scale = this.scale;
var prerendering_enabled = false;
if (NR_PAGES_TO_PRERENDER_ON_ZOOM > 0) {
// Immediate rendering optimizations enabled to improve reactiveness while zooming
// Find out which pages are visible
var min_visible, max_visible;
min_visible = max_visible = active_page.n;
while (min_visible > 0 && this.pages[min_visible].is_visible()) { min_visible-- }
while (max_visible < this.pages.length && this.pages[max_visible].is_visible()) { max_visible++ }
// If less then the threshold, enable prerendering on selected pages
if (max_visible - min_visible - 2 < NR_PAGES_TO_PRERENDER_ON_ZOOM)
prerendering_enabled = true;
}
// Set new scale
if (is_relative)
this.scale *= ratio;
@ -346,41 +364,45 @@ var pdf2htmlEX = (function(){
// Rescale pages
var pl = this.pages;
for(var i in pl) {
pl[i].rescale(this.scale);
if (prerendering_enabled && i > min_visible && i < max_visible) {
pl[i].rescale(this.scale, true);
pl[i].show(); // Force immediate refresh
} else
pl[i].rescale(this.scale); // Delayed refresh
}
// Correct container scroll to keep view aligned while zooming
var correction_top = active_page.$p.offset().top - prev_offset.top;
this.$container.scrollTop( this.$container.scrollTop() + correction_top + offsetY);
this.$container.scrollTop( this.$container.scrollTop() + correction_top + offsetY );
// Take the center of the view as a reference
var prev_center_x = this.$container.width() / 2 - prev_offset.left;
// Calculate the difference respect the center of the view after the zooming
var correction_left = prev_center_x * (this.scale/old_scale - 1) + active_page.$p.offset().left - prev_offset.left;
// Scroll the container accordingly to keep alignment to the initial reference
this.$container.scrollLeft( this.$container.scrollLeft() + correction_left + offsetX);
this.$container.scrollLeft( this.$container.scrollLeft() + correction_left + offsetX );
// Delayed rendering
// Delayed rendering for pages not already shown
this.schedule_render();
},
fit_width : function () {
var active_page = this.get_active_page();
var active_page = this.get_active_page();
this.rescale($(this.$container).width() / active_page.$b.width(), false);
this.scroll_to(active_page.n, [0,0]);
this.rescale(this.$container.width() / active_page.w, false);
this.scroll_to(active_page.n, [0,0]);
},
fit_height : function () {
var active_page = this.get_active_page();
this.rescale($(this.$container).height() / active_page.$b.height(), false);
this.rescale(this.$container.height() / active_page.h, false);
this.scroll_to(active_page.n, [0,0]);
},
get_active_page : function () {
// get page that are on the center of the view //TODO better on top?!
var y_center = $(this.$container).offset().top + $(this.$container).height() / 2;
var y_center = $(this.$container).offset().top + this.$container.height() / 2;
for (var i=2; i<this.pages.length; i++) {
if (this.pages[i].$p.offset().top > y_center)
return this.pages[i-1];
@ -406,7 +428,7 @@ var pdf2htmlEX = (function(){
{
cur_pos = cur_page.position();
//get the coordinates in default user system
cur_pos = transform(cur_page.ictm, [cur_pos[0], cur_page.height()-cur_pos[1]]);
cur_pos = transform(cur_page.ictm, [cur_pos[0], cur_page.h-cur_pos[1]]);
}
var detail_str = t.attr('data-dest-detail');
@ -435,7 +457,7 @@ var pdf2htmlEX = (function(){
break;
case 'FitH':
case 'FitBH':
pos = [0, (detail[2] == null) ? cur_pos[1] : detail[2]]
pos = [0, (detail[2] == null) ? cur_pos[1] : detail[2]];
ok = true;
break;
case 'FitV':
@ -458,10 +480,10 @@ var pdf2htmlEX = (function(){
var transform_and_scroll = function() {
pos = transform(target_page.ctm, pos);
if(upside_down) {
pos[1] = target_page.height() - pos[1];
pos[1] = target_page.h - pos[1];
}
_.scroll_to(detail[0], pos);
}
};
if (target_page.loaded) {
transform_and_scroll();
@ -494,4 +516,4 @@ var pdf2htmlEX = (function(){
});
return pdf2htmlEX;
})();
})();