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