The Tor Browser: comparison mobile/android/chrome/content/ZoomHelper.js

comparison: mobile/android/chrome/content/ZoomHelper.js

mobile/android/chrome/content/ZoomHelper.js

changeset 0: 6474c204b198

equal deleted inserted replaced

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+:9a69c3b92265
+/* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this file,
+* You can obtain one at http://mozilla.org/MPL/2.0/. */
+"use strict";
+var ZoomHelper = {
+zoomInAndSnapToRange: function(aRange) {
+// aRange is always non-null here, since a check happened previously.
+let viewport = BrowserApp.selectedTab.getViewport();
+let fudge = 15; // Add a bit of fudge.
+let boundingElement = aRange.offsetNode;
+while (!boundingElement.getBoundingClientRect && boundingElement.parentNode) {
+boundingElement = boundingElement.parentNode;
+}
+let rect = ElementTouchHelper.getBoundingContentRect(boundingElement);
+let drRect = aRange.getClientRect();
+let scrollTop =
+BrowserApp.selectedBrowser.contentDocument.documentElement.scrollTop ||
+BrowserApp.selectedBrowser.contentDocument.body.scrollTop;
+// We subtract half the height of the viewport so that we can (ideally)
+// center the area of interest on the screen.
+let topPos = scrollTop + drRect.top - (viewport.cssHeight / 2.0);
+// Factor in the border and padding
+let boundingStyle = window.getComputedStyle(boundingElement);
+let leftAdjustment = parseInt(boundingStyle.paddingLeft) +
+parseInt(boundingStyle.borderLeftWidth);
+BrowserApp.selectedTab._mReflozPositioned = true;
+rect.type = "Browser:ZoomToRect";
+rect.x = Math.max(viewport.cssPageLeft, rect.x  - fudge + leftAdjustment);
+rect.y = Math.max(topPos, viewport.cssPageTop);
+rect.w = viewport.cssWidth;
+rect.h = viewport.cssHeight;
+rect.animate = false;
+sendMessageToJava(rect);
+BrowserApp.selectedTab._mReflozPoint = null;
+},
+zoomOut: function() {
+BrowserEventHandler.resetMaxLineBoxWidth();
+sendMessageToJava({ type: "Browser:ZoomToPageWidth" });
+},
+isRectZoomedIn: function(aRect, aViewport) {
+// This function checks to see if the area of the rect visible in the
+// viewport (i.e. the "overlapArea" variable below) is approximately
+// the max area of the rect we can show. It also checks that the rect
+// is actually on-screen by testing the left and right edges of the rect.
+// In effect, this tells us whether or not zooming in to this rect
+// will significantly change what the user is seeing.
+const minDifference = -20;
+const maxDifference = 20;
+const maxZoomAllowed = 4; // keep this in sync with mobile/android/base/ui/PanZoomController.MAX_ZOOM
+let vRect = new Rect(aViewport.cssX, aViewport.cssY, aViewport.cssWidth, aViewport.cssHeight);
+let overlap = vRect.intersect(aRect);
+let overlapArea = overlap.width * overlap.height;
+let availHeight = Math.min(aRect.width * vRect.height / vRect.width, aRect.height);
+let showing = overlapArea / (aRect.width * availHeight);
+let dw = (aRect.width - vRect.width);
+let dx = (aRect.x - vRect.x);
+if (fuzzyEquals(aViewport.zoom, maxZoomAllowed) && overlap.width / aRect.width > 0.9) {
+// we're already at the max zoom and the block is not spilling off the side of the screen so that even
+// if the block isn't taking up most of the viewport we can't pan/zoom in any more. return true so that we zoom out
+return true;
+}
+return (showing > 0.9 &&
+dx > minDifference && dx < maxDifference &&
+dw > minDifference && dw < maxDifference);
+},
+/* Zoom to an element, optionally keeping a particular part of it
+* in view if it is really tall.
+*/
+zoomToElement: function(aElement, aClickY = -1, aCanZoomOut = true, aCanScrollHorizontally = true) {
+let rect = ElementTouchHelper.getBoundingContentRect(aElement);
+ZoomHelper.zoomToRect(rect, aClickY, aCanZoomOut, aCanScrollHorizontally, aElement);
+},
+zoomToRect: function(aRect, aClickY = -1, aCanZoomOut = true, aCanScrollHorizontally = true, aElement) {
+const margin = 15;
+if(!aRect.h || !aRect.w) {
+aRect.h = aRect.height;
+aRect.w = aRect.width;
+}
+let viewport = BrowserApp.selectedTab.getViewport();
+let bRect = new Rect(aCanScrollHorizontally ? Math.max(viewport.cssPageLeft, aRect.x - margin) : viewport.cssX,
+aRect.y,
+aCanScrollHorizontally ? aRect.w + 2 * margin : viewport.cssWidth,
+aRect.h);
+// constrict the rect to the screen's right edge
+bRect.width = Math.min(bRect.width, viewport.cssPageRight - bRect.x);
+// if the rect is already taking up most of the visible area and is stretching the
+// width of the page, then we want to zoom out instead.
+if (aElement) {
+if (BrowserEventHandler.mReflozPref) {
+let zoomFactor = BrowserApp.selectedTab.getZoomToMinFontSize(aElement);
+bRect.width = zoomFactor <= 1.0 ? bRect.width : gScreenWidth / zoomFactor;
+bRect.height = zoomFactor <= 1.0 ? bRect.height : bRect.height / zoomFactor;
+if (zoomFactor == 1.0 || ZoomHelper.isRectZoomedIn(bRect, viewport)) {
+if (aCanZoomOut) {
+ZoomHelper.zoomOut();
+}
+return;
+}
+} else if (ZoomHelper.isRectZoomedIn(bRect, viewport)) {
+if (aCanZoomOut) {
+ZoomHelper.zoomOut();
+}
+return;
+}
+}
+let rect = {};
+rect.type = "Browser:ZoomToRect";
+rect.x = bRect.x;
+rect.y = bRect.y;
+rect.w = bRect.width;
+rect.h = Math.min(bRect.width * viewport.cssHeight / viewport.cssWidth, bRect.height);
+if (aClickY >= 0) {
+// if the block we're zooming to is really tall, and we want to keep a particular
+// part of it in view, then adjust the y-coordinate of the target rect accordingly.
+// the 1.2 multiplier is just a little fuzz to compensate for bRect including horizontal
+// margins but not vertical ones.
+let cssTapY = viewport.cssY + aClickY;
+if ((bRect.height > rect.h) && (cssTapY > rect.y + (rect.h * 1.2))) {
+rect.y = cssTapY - (rect.h / 2);
+}
+}
+if (rect.w > viewport.cssWidth || rect.h > viewport.cssHeight) {
+BrowserEventHandler.resetMaxLineBoxWidth();
+}
+sendMessageToJava(rect);
+},
+};