commit 6a513fb6adc87b6e7e6f6046ee5fc52ac50f1231 Author: Richard Pospesel richard@torproject.org Date: Mon Oct 28 17:42:17 2019 -0700

Bug 32220: Improve the letterboxing experience

CSS and JS changes to alter the UX surrounding letterboxing. The browser element containing page content is now anchored to the bottom of the toolbar, and the remaining letterbox margin is the same color as the firefox chrome. The letterbox margin and border are tied to the currently selected theme.

Also adds a 'needsLetterbox' property to tabbrowser.xml to fix a race condition present when using the 'isEmpty' property. Using 'isEmpty' as a proxy for 'needsLetterbox' resulted in over-zealous/unnecessary letterboxing of about:blank tabs. --- browser/base/content/browser.css | 8 ++ browser/base/content/tabbrowser-tab.js | 9 +++ browser/themes/shared/tabs.inc.css | 6 ++ .../components/resistfingerprinting/RFPHelper.jsm | 94 +++++++++++++++++++--- 4 files changed, 105 insertions(+), 12 deletions(-)

diff --git a/browser/base/content/browser.css b/browser/base/content/browser.css index 808c03e88223..a0b1bf4a8951 100644 --- a/browser/base/content/browser.css +++ b/browser/base/content/browser.css @@ -85,6 +85,14 @@ body { display: none; }

+ +.browserStack > browser.letterboxing { + border-color: var(--chrome-content-separator-color); + border-style: solid; + border-width : 1px; + border-top: none; +} + %ifdef MENUBAR_CAN_AUTOHIDE #toolbar-menubar[autohide="true"] { overflow: hidden; diff --git a/browser/base/content/tabbrowser-tab.js b/browser/base/content/tabbrowser-tab.js index 183eff1bab86..7f376ab1d122 100644 --- a/browser/base/content/tabbrowser-tab.js +++ b/browser/base/content/tabbrowser-tab.js @@ -225,6 +225,15 @@ return true; }

+ get needsLetterbox() { + let browser = this.linkedBrowser; + if (isBlankPageURL(browser.currentURI.spec)) { + return false; + } + + return true; + } + get lastAccessed() { return this._lastAccessed == Infinity ? Date.now() : this._lastAccessed; } diff --git a/browser/themes/shared/tabs.inc.css b/browser/themes/shared/tabs.inc.css index b47842af766c..019da6ecf76f 100644 --- a/browser/themes/shared/tabs.inc.css +++ b/browser/themes/shared/tabs.inc.css @@ -33,6 +33,12 @@ background-color: #f9f9fa; }

+/* extend down the toolbar's colors when letterboxing is enabled*/ +#tabbrowser-tabpanels.letterboxing { + background-color: var(--toolbar-bgcolor); + background-image: var(--toolbar-bgimage); +} + :root[privatebrowsingmode=temporary] #tabbrowser-tabpanels { /* Value for --in-content-page-background in aboutPrivateBrowsing.css */ background-color: #25003e; diff --git a/toolkit/components/resistfingerprinting/RFPHelper.jsm b/toolkit/components/resistfingerprinting/RFPHelper.jsm index 49010d1c8cb1..b906a067fd63 100644 --- a/toolkit/components/resistfingerprinting/RFPHelper.jsm +++ b/toolkit/components/resistfingerprinting/RFPHelper.jsm @@ -40,6 +40,7 @@ class _RFPHelper { // ============================================================================ constructor() { this._initialized = false; + this._borderDimensions = null; }

init() { @@ -361,6 +362,24 @@ class _RFPHelper { }); }

+ getBorderDimensions(aBrowser) { + if (this._borderDimensions) { + return this._borderDimensions; + } + + const win = aBrowser.ownerGlobal; + const browserStyle = win.getComputedStyle(aBrowser); + + this._borderDimensions = { + top : parseInt(browserStyle.borderTopWidth), + right: parseInt(browserStyle.borderRightWidth), + bottom : parseInt(browserStyle.borderBottomWidth), + left : parseInt(browserStyle.borderLeftWidth), + }; + + return this._borderDimensions; + } + _addOrClearContentMargin(aBrowser) { let tab = aBrowser.getTabBrowser().getTabForBrowser(aBrowser);

@@ -369,9 +388,13 @@ class _RFPHelper { return; }

+ // we add the letterboxing class even if the content does not need letterboxing + // in which case margins are set such that the borders are hidden + aBrowser.classList.add("letterboxing"); + // We should apply no margin around an empty tab or a tab with system // principal. - if (tab.isEmpty || aBrowser.contentPrincipal.isSystemPrincipal) { + if (!tab.needsLetterbox || aBrowser.contentPrincipal.isSystemPrincipal) { this._clearContentViewMargin(aBrowser); } else { this._roundContentView(aBrowser); @@ -539,10 +562,29 @@ class _RFPHelper { // Calculating the margins around the browser element in order to round the // content viewport. We will use a 200x100 stepping if the dimension set // is not given. - let margins = calcMargins(containerWidth, containerHeight); + + const borderDimensions = this.getBorderDimensions(aBrowser); + const marginDims = calcMargins(containerWidth, containerHeight - borderDimensions.top); + + let margins = { + top : 0, + right : 0, + bottom : 0, + left : 0, + }; + + // snap browser element to top + margins.top = 0; + // and leave 'double' margin at the bottom + margins.bottom = 2 * marginDims.height - borderDimensions.bottom; + // identical margins left and right + margins.right = marginDims.width - borderDimensions.right; + margins.left = marginDims.width - borderDimensions.left; + + const marginStyleString = `${margins.top}px ${margins.right}px ${margins.bottom}px ${margins.left}px`;

// If the size of the content is already quantized, we do nothing. - if (aBrowser.style.margin == `${margins.height}px ${margins.width}px`) { + if (aBrowser.style.margin === marginStyleString) { log("_roundContentView[" + logId + "] is_rounded == true"); if (this._isLetterboxingTesting) { log( @@ -563,19 +605,35 @@ class _RFPHelper { "_roundContentView[" + logId + "] setting margins to " + - margins.width + - " x " + - margins.height + marginStyleString ); - // One cannot (easily) control the color of a margin unfortunately. - // An initial attempt to use a border instead of a margin resulted - // in offset event dispatching; so for now we use a colorless margin. - aBrowser.style.margin = `${margins.height}px ${margins.width}px`; + + // The margin background color is determined by the background color of the + // window's tabpanels#tabbrowser-tabpanels element + aBrowser.style.margin = marginStyleString; }); }

_clearContentViewMargin(aBrowser) { + const borderDimensions = this.getBorderDimensions(aBrowser); + // set the margins such that the browser elements border is visible up top, but + // are rendered off-screen on the remaining sides + let margins = { + top : 0, + right : -borderDimensions.right, + bottom : -borderDimensions.bottom, + left : -borderDimensions.left, + }; + const marginStyleString = `${margins.top}px ${margins.right}px ${margins.bottom}px ${margins.left}px`; + + aBrowser.ownerGlobal.requestAnimationFrame(() => { + aBrowser.style.margin = marginStyleString; + }); + } + + _removeLetterboxing(aBrowser) { aBrowser.ownerGlobal.requestAnimationFrame(() => { + aBrowser.classList.remove("letterboxing"); aBrowser.style.margin = ""; }); } @@ -593,6 +651,11 @@ class _RFPHelper { aWindow.gBrowser.addTabsProgressListener(this); aWindow.addEventListener("TabOpen", this);

+ const tabPanel = aWindow.document.getElementById("tabbrowser-tabpanels"); + if (tabPanel) { + tabPanel.classList.add("letterboxing"); + } + // Rounding the content viewport. this._updateMarginsForTabsInWindow(aWindow); } @@ -616,10 +679,17 @@ class _RFPHelper { tabBrowser.removeTabsProgressListener(this); aWindow.removeEventListener("TabOpen", this);

- // Clear all margins and tooltip for all browsers. + // revert tabpanel's background colors to default + const tabPanel = aWindow.document.getElementById("tabbrowser-tabpanels"); + if (tabPanel) { + tabPanel.classList.remove("letterboxing"); + } + + // and revert each browser element to default, + // restore default margins and remove letterboxing class for (let tab of tabBrowser.tabs) { let browser = tab.linkedBrowser; - this._clearContentViewMargin(browser); + this._removeLetterboxing(browser); } }