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pcjs/modules/pc6502/lib/video.js

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/**
* @fileoverview Implements the PC6502 Video component.
* @author <a href="mailto:Jeff@pcjs.org">Jeff Parsons</a>
* @version 1.0
* Created 2016-May-12
*
* Copyright © 2012-2016 Jeff Parsons <Jeff@pcjs.org>
*
* This file is part of PCjs, which is part of the JavaScript Machines Project (aka JSMachines)
* at <http://jsmachines.net/> and <http://pcjs.org/>.
*
* PCjs is free software: you can redistribute it and/or modify it under the terms of the
* GNU General Public License as published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* PCjs is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with PCjs. If not,
* see <http://www.gnu.org/licenses/gpl.html>.
*
* You are required to include the above copyright notice in every source code file of every
* copy or modified version of this work, and to display that copyright notice on every screen
* that loads or runs any version of this software (see Computer.COPYRIGHT).
*
* Some PCjs files also attempt to load external resource files, such as character-image files,
* ROM files, and disk image files. Those external resource files are not considered part of the
* PCjs program for purposes of the GNU General Public License, and the author does not claim
* any copyright as to their contents.
*/
"use strict";
if (NODE) {
var str = require("../../shared/lib/strlib");
var web = require("../../shared/lib/weblib");
var DumpAPI = require("../../shared/lib/dumpapi");
var Component = require("../../shared/lib/component");
var Memory = require("./memory");
var Messages = require("./messages");
var State = require("./state");
}
/**
* Video(parmsVideo, canvas, context, textarea, container)
*
* The Video component can be configured with the following (parmsVideo) properties:
*
* screenWidth: width of the screen canvas, in pixels
* screenHeight: height of the screen canvas, in pixels
* screenColor: background color of the screen canvas (default is black)
* screenRotate: the amount of counter-clockwise screen rotation required (eg, -90 or 270)
* aspectRatio (eg, 1.33)
* bufferAddr: the starting address of the frame buffer (eg, 0x2400)
* bufferCols: the width of a single frame buffer row, in pixels (eg, 256)
* bufferRows: the number of frame buffer rows (eg, 224)
* bufferBits: the number of bits per column (default is 1)
* bufferLeft: the bit position of the left-most pixel in a byte (default is 0; CGA uses 7)
* bufferRotate: the amount of counter-clockwise buffer rotation required (eg, -90 or 270)
* interruptRate: normally the same as (or some multiple of) refreshRate (eg, 120)
* refreshRate: how many times updateScreen() should be performed per second (eg, 60)
*
* We record all the above values now, but we defer creation of the frame buffer until our initBus()
* handler is called. At that point, we will also compute the extent of the frame buffer, determine the
* appropriate "cell" size (ie, the number of pixels that updateScreen() will fetch and process at once),
* and then allocate our cell cache.
*
* Why interruptRate in addition to refreshRate? A higher interrupt rate is required for Space Invaders,
* because even though the CRT refreshes at 60Hz, the CRT controller interrupts the CPU *twice* per
* refresh (once after the top half of the screen has been redrawn, and again after the bottom half has
* been redrawn), so we need an interrupt rate of 120Hz. We pass the higher rate on to the CPU, so that
* it will call updateScreen() more frequently, but we still limit our screen updates to every *other* call.
*
* bufferRotate is an alternative to screenRotate; you may set one or the other (but not both) to -90 to
* enable different approaches to counter-clockwise 90-degree image rotation. screenRotate uses canvas
* transformation methods (translate(), rotate(), and scale()), while bufferRotate inverts the dimensions
* of the off-screen buffer and then relies on setPixel() to "rotate" the data into it.
*
* @constructor
* @extends Component
* @param {Object} parmsVideo
* @param {Object} [canvas]
* @param {Object} [context]
* @param {Object} [textarea]
* @param {Object} [container]
*/
function Video(parmsVideo, canvas, context, textarea, container)
{
var video = this;
this.fGecko = web.isUserAgent("Gecko/");
var i, sEvent, asWebPrefixes = ['', 'moz', 'ms', 'webkit'];
Component.call(this, "Video", parmsVideo, Video, Messages.VIDEO);
this.cxScreen = parmsVideo['screenWidth'];
this.cyScreen = parmsVideo['screenHeight'];
this.addrBuffer = parmsVideo['bufferAddr'];
this.cxBuffer = parmsVideo['bufferCols'];
this.cyBuffer = parmsVideo['bufferRows'];
this.nBitsPerPixel = parmsVideo['bufferBits'] || 1;
this.iBitFirstPixel = parmsVideo['bufferLeft'] || 0;
this.rotateBuffer = parmsVideo['bufferRotate'];
if (this.rotateBuffer) {
this.rotateBuffer = this.rotateBuffer % 360;
if (this.rotateBuffer > 0) this.rotateBuffer -= 360;
if (this.rotateBuffer != -90) {
this.notice("unsupported buffer rotation: " + this.rotateBuffer);
this.rotateBuffer = 0;
}
}
this.interruptRate = parmsVideo['interruptRate'];
this.refreshRate = parmsVideo['refreshRate'] || 60;
this.canvasScreen = canvas;
this.contextScreen = context;
this.textareaScreen = textarea;
this.inputScreen = textarea || canvas || null;
/*
* Support for disabling (or, less commonly, enabling) image smoothing, which all browsers
* seem to support now (well, OK, I still have to test the latest MS Edge browser), despite
* it still being labelled "experimental technology". Let's hope the browsers standardize
* on this. I see other options emerging, like the CSS property "image-rendering: pixelated"
* that's apparently been added to Chrome. Sigh.
*/
var fSmoothing = parmsVideo['smoothing'];
var sSmoothing = Component.parmsURL['smoothing'];
if (sSmoothing) fSmoothing = (sSmoothing == "true");
if (fSmoothing != null) {
for (i = 0; i < asWebPrefixes.length; i++) {
sEvent = asWebPrefixes[i];
if (!sEvent) {
sEvent = 'imageSmoothingEnabled';
} else {
sEvent += 'ImageSmoothingEnabled';
}
if (this.contextScreen[sEvent] !== undefined) {
this.contextScreen[sEvent] = fSmoothing;
break;
}
}
}
this.rotateScreen = parmsVideo['screenRotate'];
if (this.rotateScreen) {
this.rotateScreen = this.rotateScreen % 360;
if (this.rotateScreen > 0) this.rotateScreen -= 360;
if (this.rotateScreen != -90) {
this.notice("unsupported screen rotation: " + this.rotateScreen);
this.rotateScreen = 0;
} else {
this.contextScreen.translate(0, this.cyScreen);
this.contextScreen.rotate((this.rotateScreen * Math.PI)/180);
this.contextScreen.scale(this.cyScreen/this.cxScreen, this.cxScreen/this.cyScreen);
}
}
this.initColors();
/*
* Allocate off-screen buffers.
*/
var cxBuffer = this.cxBuffer;
var cyBuffer = this.cyBuffer;
if (this.rotateBuffer) {
cxBuffer = this.cyBuffer;
cyBuffer = this.cxBuffer;
}
this.imageBuffer = this.contextScreen.createImageData(cxBuffer, cyBuffer);
this.canvasBuffer = document.createElement("canvas");
this.canvasBuffer.width = cxBuffer;
this.canvasBuffer.height = cyBuffer;
this.contextBuffer = this.canvasBuffer.getContext("2d");
/*
* Here's the gross code to handle full-screen support across all supported browsers. The lack of standards
* is exasperating; browsers can't agree on 'full' or 'Full, 'request' or 'Request', 'screen' or 'Screen', and
* while some browsers honor other browser prefixes, most browsers don't.
*/
this.container = container;
if (this.container) {
this.container.doFullScreen = container['requestFullscreen'] || container['msRequestFullscreen'] || container['mozRequestFullScreen'] || container['webkitRequestFullscreen'];
if (this.container.doFullScreen) {
for (i = 0; i < asWebPrefixes.length; i++) {
sEvent = asWebPrefixes[i] + 'fullscreenchange';
if ('on' + sEvent in document) {
var onFullScreenChange = function() {
var fFullScreen = (document['fullscreenElement'] || document['msFullscreenElement'] || document['mozFullScreenElement'] || document['webkitFullscreenElement']);
video.notifyFullScreen(fFullScreen? true : false);
};
document.addEventListener(sEvent, onFullScreenChange, false);
break;
}
}
for (i = 0; i < asWebPrefixes.length; i++) {
sEvent = asWebPrefixes[i] + 'fullscreenerror';
if ('on' + sEvent in document) {
var onFullScreenError = function() {
video.notifyFullScreen(null);
};
document.addEventListener(sEvent, onFullScreenError, false);
break;
}
}
}
}
}
Component.subclass(Video);
Video.COLORS = {
OVERLAY_TOP: 0,
OVERLAY_BOTTOM: 1,
OVERLAY_TOTAL: 2
};
/**
* initBus(cmp, bus, cpu, dbg)
*
* @this {Video}
* @param {Computer} cmp
* @param {Bus} bus
* @param {CPUState} cpu
* @param {Debugger} dbg
*/
Video.prototype.initBus = function(cmp, bus, cpu, dbg)
{
this.cmp = cmp;
this.bus = bus;
this.cpu = cpu;
this.dbg = dbg;
/*
* Compute the size of the frame buffer and allocate.
*/
this.sizeBuffer = ((this.cxBuffer * this.nBitsPerPixel) >> 3) * this.cyBuffer;
if (this.bus.addMemory(this.addrBuffer, this.sizeBuffer, Memory.TYPE.VIDEO)) {
/*
* Compute the number of cells and initialize the cell cache.
*/
this.nCellCache = this.sizeBuffer >> 1;
this.nPixelsPerCell = (16 / this.nBitsPerPixel)|0;
this.initCache();
}
this.setReady();
};
/**
* setBinding(sHTMLType, sBinding, control, sValue)
*
* @this {Video}
* @param {string|null} sHTMLType is the type of the HTML control (eg, "button", "list", "text", "submit", "textarea", "canvas")
* @param {string} sBinding is the value of the 'binding' parameter stored in the HTML control's "data-value" attribute (eg, "refresh")
* @param {Object} control is the HTML control DOM object (eg, HTMLButtonElement)
* @param {string} [sValue] optional data value
* @return {boolean} true if binding was successful, false if unrecognized binding request
*/
Video.prototype.setBinding = function(sHTMLType, sBinding, control, sValue)
{
var video = this;
switch (sBinding) {
case "fullScreen":
this.bindings[sBinding] = control;
if (this.container && this.container.doFullScreen) {
control.onclick = function onClickFullScreen() {
if (DEBUG) video.printMessage("fullScreen()");
video.doFullScreen();
};
} else {
if (DEBUG) this.log("FullScreen API not available");
control.parentNode.removeChild(/** @type {Node} */ (control));
}
return true;
default:
break;
}
return false;
};
/**
* doFullScreen()
*
* @this {Video}
* @return {boolean} true if request successful, false if not (eg, failed OR not supported)
*/
Video.prototype.doFullScreen = function()
{
var fSuccess = false;
if (this.container) {
if (this.container.doFullScreen) {
/*
* Styling the container with a width of "100%" and a height of "auto" works great when the aspect ratio
* of our virtual screen is at least roughly equivalent to the physical screen's aspect ratio, but now that
* we support virtual VGA screens with an aspect ratio of 1.33, that's very much out of step with modern
* wide-screen monitors, which usually have an aspect ratio of 1.6 or greater.
*
* And unfortunately, none of the browsers I've tested appear to make any attempt to scale our container to
* the physical screen's dimensions, so the bottom of our screen gets clipped. To prevent that, I reduce
* the width from 100% to whatever percentage will accommodate the entire height of the virtual screen.
*
* NOTE: Mozilla recommends both a width and a height of "100%", but all my tests suggest that using "auto"
* for height works equally well, so I'm sticking with it, because "auto" is also consistent with how I've
* implemented a responsive canvas when the browser window is being resized.
*/
var sWidth = "100%";
var sHeight = "auto";
if (screen && screen.width && screen.height) {
var aspectPhys = screen.width / screen.height;
var aspectVirt = this.cxScreen / this.cyScreen;
if (aspectPhys > aspectVirt) {
sWidth = Math.round(aspectVirt / aspectPhys * 100) + '%';
}
// TODO: We may need to someday consider the case of a physical screen with an aspect ratio < 1.0....
}
if (!this.fGecko) {
this.container.style.width = sWidth;
this.container.style.height = sHeight;
} else {
/*
* Sadly, the above code doesn't work for Firefox, because as http://developer.mozilla.org/en-US/docs/Web/Guide/API/DOM/Using_full_screen_mode
* explains:
*
* 'It's worth noting a key difference here between the Gecko and WebKit implementations at this time:
* Gecko automatically adds CSS rules to the element to stretch it to fill the screen: "width: 100%; height: 100%".
*
* Which would be OK if Gecko did that BEFORE we're called, but apparently it does that AFTER, effectively
* overwriting our careful calculations. So we style the inner element (canvasScreen) instead, which
* requires even more work to ensure that the canvas is properly centered. FYI, this solution is consistent
* with Mozilla's recommendation for working around their automatic CSS rules:
*
* '[I]f you're trying to emulate WebKit's behavior on Gecko, you need to place the element you want
* to present inside another element, which you'll make fullscreen instead, and use CSS rules to adjust
* the inner element to match the appearance you want.'
*/
this.canvasScreen.style.width = sWidth;
this.canvasScreen.style.width = sWidth;
this.canvasScreen.style.display = "block";
this.canvasScreen.style.margin = "auto";
}
this.container.style.backgroundColor = "black";
this.container.doFullScreen();
fSuccess = true;
}
this.setFocus();
}
return fSuccess;
};
/**
* notifyFullScreen(fFullScreen)
*
* @this {Video}
* @param {boolean|null} fFullScreen (null if there was a full-screen error)
*/
Video.prototype.notifyFullScreen = function(fFullScreen)
{
if (!fFullScreen && this.container) {
if (!this.fGecko) {
this.container.style.width = this.container.style.height = "";
} else {
this.canvasScreen.style.width = this.canvasScreen.style.height = "";
}
}
this.printMessage("notifyFullScreen(" + fFullScreen + ")", true);
};
/**
* setFocus()
*
* @this {Video}
*/
Video.prototype.setFocus = function()
{
if (this.inputScreen) this.inputScreen.focus();
};
/**
* getRefreshRate()
*
* @this {Video}
* @return {number}
*/
Video.prototype.getRefreshRate = function()
{
return Math.max(this.refreshRate, this.interruptRate);
};
/**
* initCache()
*
* Initializes the contents of our internal cell cache.
*
* @this {Video}
*/
Video.prototype.initCache = function()
{
this.fCellCacheValid = false;
if (this.aCellCache === undefined || this.aCellCache.length != this.nCellCache) {
this.aCellCache = new Array(this.nCellCache);
}
};
/**
* initColors()
*
* This creates an array of nColors, with additional OVERLAY_TOTAL colors tacked on to the end of the array.
*
* @this {Video}
*/
Video.prototype.initColors = function()
{
var rgbBlack = [0x00, 0x00, 0x00, 0xff];
var rgbWhite = [0xff, 0xff, 0xff, 0xff];
var rgbGreen = [0x00, 0xff, 0x00, 0xff];
var rgbYellow = [0xff, 0xff, 0x00, 0xff];
this.nColors = (1 << this.nBitsPerPixel);
this.aRGB = new Array(this.nColors + Video.COLORS.OVERLAY_TOTAL);
this.aRGB[0] = rgbBlack;
this.aRGB[1] = rgbWhite;
this.aRGB[this.nColors + Video.COLORS.OVERLAY_TOP] = rgbYellow;
this.aRGB[this.nColors + Video.COLORS.OVERLAY_BOTTOM] = rgbGreen;
};
/**
* setPixel(imageBuffer, x, y, bPixel)
*
* @this {Video}
* @param {Object} imageBuffer
* @param {number} x
* @param {number} y
* @param {number} bPixel (ie, an index into aRGB)
*/
Video.prototype.setPixel = function(imageBuffer, x, y, bPixel)
{
var index;
if (!this.rotateBuffer) {
index = (x + y * imageBuffer.width);
} else {
index = (imageBuffer.height - x - 1) * imageBuffer.width + y;
}
if (bPixel) {
if (x >= 208 && x < 236) {
bPixel = this.nColors + Video.COLORS.OVERLAY_TOP;
}
else if (x >= 28 && x < 72) {
bPixel = this.nColors + Video.COLORS.OVERLAY_BOTTOM;
}
}
var rgb = this.aRGB[bPixel];
index *= rgb.length;
imageBuffer.data[index] = rgb[0];
imageBuffer.data[index+1] = rgb[1];
imageBuffer.data[index+2] = rgb[2];
imageBuffer.data[index+3] = rgb[3];
};
/**
* updateScreen(n)
*
* Propagates the video buffer to the cell cache and updates the screen with any changes. Forced updates
* are generally internal updates triggered by an I/O operation or other state change, while non-forced updates
* are the periodic updates coming from the CPU.
*
* For every cell in the video buffer, compare it to the cell stored in the cell cache, render if it differs,
* and then update the cell cache to match. Since initCache() sets every cell in the cell cache to an
* invalid value, we're assured that the next call to updateScreen() will redraw the entire (visible) video buffer.
*
* @this {Video}
* @param {number} n (where 0 <= n < getRefreshRate() for a normal update, or -1 for a forced update)
*/
Video.prototype.updateScreen = function(n)
{
if (n >= 0) {
if (!(n & 1)) {
/*
* On even updates, call cpu.requestINTR(1), and also update our copy of the screen.
*/
this.cpu.requestINTR(1);
} else {
/*
* On odd updates, call cpu.requestINTR(2), but do NOT update our copy of the screen, because
* the machine has presumably only updated the top half of the frame buffer at this point; it will
* update the bottom half of the frame buffer after acknowledging this interrupt.
*/
this.cpu.requestINTR(2);
return;
}
/*
* Since this is not a forced update, if our cell cache is valid AND the buffer is clean, then do nothing.
*/
if (this.fCellCacheValid && this.bus.cleanMemory(this.addrBuffer, this.sizeBuffer)) {
return;
}
}
var addr = this.addrBuffer;
var addrLimit = addr + this.sizeBuffer;
var iCell = 0;
var nPixelShift = 1;
var xBuffer = 0, yBuffer = 0;
var xDirty = this.cxBuffer, xMaxDirty = 0, yDirty = this.cyBuffer, yMaxDirty = 0;
var nShiftInit = 0;
var nShiftPixel = this.nBitsPerPixel;
var nMask = (1 << nShiftPixel) - 1;
if (this.iBitFirstPixel) {
nShiftPixel = -nShiftPixel;
nShiftInit = 16 + nShiftPixel;
}
while (addr < addrLimit) {
var data = this.bus.getShortDirect(addr);
this.assert(iCell < this.aCellCache.length);
if (this.fCellCacheValid && data === this.aCellCache[iCell]) {
xBuffer += this.nPixelsPerCell;
} else {
this.aCellCache[iCell] = data;
var nShift = nShiftInit;
if (nShift) data = ((data >> 8) | ((data & 0xff) << 8));
if (xBuffer < xDirty) xDirty = xBuffer;
var cPixels = this.nPixelsPerCell;
while (cPixels--) {
var bPixel = (data >> nShift) & nMask;
this.setPixel(this.imageBuffer, xBuffer++, yBuffer, bPixel);
nShift += nShiftPixel;
}
if (xBuffer > xMaxDirty) xMaxDirty = xBuffer;
if (yBuffer < yDirty) yDirty = yBuffer;
if (yBuffer >= yMaxDirty) yMaxDirty = yBuffer + 1;
}
addr += 2; iCell++;
if (xBuffer >= this.cxBuffer) {
xBuffer = 0; yBuffer++;
if (yBuffer > this.cyBuffer) break;
}
}
this.fCellCacheValid = true;
/*
* Instead of blasting the ENTIRE imageBuffer into contextBuffer, and then blasting the ENTIRE
* canvasBuffer onto contextScreen, even for the smallest change, let's try to be a bit smarter about
* the update (well, to the extent that the canvas APIs permit).
*/
if (xDirty < this.cxBuffer) {
var cxDirty = xMaxDirty - xDirty;
var cyDirty = yMaxDirty - yDirty;
if (this.rotateBuffer) {
/*
* If rotateBuffer is set, then it must be -90, so we must "rotate" the dirty coordinates as well,
* because they are relative to the frame buffer, not the rotated image buffer. Alternatively, you
* can use the following call to blast the ENTIRE imageBuffer into contextBuffer instead:
*
* this.contextBuffer.putImageData(this.imageBuffer, 0, 0);
*/
var xDirtyOrig = xDirty, cxDirtyOrig = cxDirty;
//noinspection JSSuspiciousNameCombination
xDirty = yDirty;
cxDirty = cyDirty;
yDirty = this.cxBuffer - (xDirtyOrig + cxDirtyOrig);
cyDirty = cxDirtyOrig;
}
this.contextBuffer.putImageData(this.imageBuffer, 0, 0, xDirty, yDirty, cxDirty, cyDirty);
this.contextScreen.drawImage(this.canvasBuffer, 0, 0, this.canvasBuffer.width, this.canvasBuffer.height, 0, 0, this.cxScreen, this.cyScreen);
}
};
/**
* Video.init()
*
* This function operates on every HTML element of class "video", extracting the
* JSON-encoded parameters for the Video constructor from the element's "data-value"
* attribute, invoking the constructor to create a Video component, and then binding
* any associated HTML controls to the new component.
*/
Video.init = function()
{
var aeVideo = Component.getElementsByClass(document, APPCLASS, "video");
for (var iVideo = 0; iVideo < aeVideo.length; iVideo++) {
var eVideo = aeVideo[iVideo];
var parmsVideo = Component.getComponentParms(eVideo);
var eCanvas = document.createElement("canvas");
if (eCanvas === undefined || !eCanvas.getContext) {
eVideo.innerHTML = "<br/>Missing &lt;canvas&gt; support. Please try a newer web browser.";
return;
}
eCanvas.setAttribute("class", "pcjs-canvas");
eCanvas.setAttribute("width", parmsVideo['screenWidth']);
eCanvas.setAttribute("height", parmsVideo['screenHeight']);
eCanvas.style.backgroundColor = parmsVideo['screenColor'];
/*
* The "contenteditable" attribute on a canvas element NOTICEABLY slows down canvas drawing on
* Safari as soon as you give the canvas focus (ie, click away from the canvas, and drawing speeds
* up; click on the canvas, and drawing slows down). So the "transparent textarea hack" that we
* once employed as only a work-around for Android devices is now our default.
*
* eCanvas.setAttribute("contenteditable", "true");
*
* HACK: A canvas style of "auto" provides for excellent responsive canvas scaling in EVERY browser
* except IE9/IE10, so I recalculate the appropriate CSS height every time the parent DIV is resized;
* IE11 works without this hack, so we take advantage of the fact that IE11 doesn't identify as "MSIE".
*
* The other reason it's good to keep this particular hack limited to IE9/IE10 is that most other
* browsers don't actually support an 'onresize' handler on anything but the window object.
*/
eCanvas.style.height = "auto";
if (web.getUserAgent().indexOf("MSIE") >= 0) {
eVideo.onresize = function(eParent, eChild, cx, cy) {
return function onResizeVideo() {
eChild.style.height = (((eParent.clientWidth * cy) / cx) | 0) + "px";
};
}(eVideo, eCanvas, parmsVideo['screenWidth'], parmsVideo['screenHeight']);
eVideo.onresize();
}
/*
* The following is a related hack that allows the user to force the screen to use a particular aspect
* ratio if an 'aspect' attribute or URL parameter is set. Initially, it's just for testing purposes
* until we figure out a better UI. And note that we use our web.onPageEvent() helper function to make
* sure we don't trample any other 'onresize' handler(s) attached to the window object.
*/
var aspect = +(parmsVideo['aspect'] || Component.parmsURL['aspect']);
/*
* No 'aspect' parameter yields NaN, which is falsey, and anything else must satisfy my arbitrary
* constraints of 0.3 <= aspect <= 3.33, to prevent any useless (or worse, browser-blowing) results.
*/
if (aspect && aspect >= 0.3 && aspect <= 3.33) {
web.onPageEvent('onresize', function(eParent, eChild, aspectRatio) {
return function onResizeWindow() {
/*
* Since aspectRatio is the target width/height, we have:
*
* eParent.clientWidth / eChild.style.height = aspectRatio
*
* which means that:
*
* eChild.style.height = eParent.clientWidth / aspectRatio
*
* so for example, if aspectRatio is 16:9, or 1.78, and clientWidth = 640,
* then the calculated height should approximately 360.
*/
eChild.style.height = ((eParent.clientWidth / aspectRatio)|0) + "px";
};
}(eVideo, eCanvas, aspect));
window['onresize']();
}
eVideo.appendChild(eCanvas);
/*
* HACK: Android-based browsers, like the Silk (Amazon) browser and Chrome for Android, don't honor the
* "contenteditable" attribute; that is, when the canvas receives focus, they don't activate the on-screen
* keyboard. So my fallback is to create a transparent textarea on top of the canvas.
*
* The parent DIV must have a style of "position:relative" (alternatively, a class of "pcjs-container"),
* so that we can position the textarea using absolute coordinates. Also, we don't want the textarea to be
* visible, but we must use "opacity:0" instead of "visibility:hidden", because the latter seems to prevent
* the element from receiving events. These styling requirements are taken care of in components.css
* (see references to the "pcjs-video-object" class).
*
* UPDATE: Unfortunately, Android keyboards like to compose whole words before transmitting any of the
* intervening characters; our textarea's keyDown/keyUp event handlers DO receive intervening key events,
* but their keyCode property is ZERO. Virtually the only usable key event we receive is the Enter key.
* Android users will have to use machines that include their own on-screen "soft keyboard", or use an
* external keyboard.
*
* The following attempt to use a password-enabled input field didn't work any better on Android. You could
* clearly see the overlaid semi-transparent input field, but none of the input characters were passed along,
* with the exception of the "Go" (Enter) key.
*
* var eInput = document.createElement("input");
* eInput.setAttribute("type", "password");
* eInput.setAttribute("style", "position:absolute; left:0; top:0; width:100%; height:100%; opacity:0.5");
* eVideo.appendChild(eInput);
*
* See this Chromium issue for more information: https://code.google.com/p/chromium/issues/detail?id=118639
*/
var eTextArea = document.createElement("textarea");
/*
* As noted in keyboard.js, the keyboard on an iOS device tends to pop up with the SHIFT key depressed,
* which is not the initial keyboard state that the Keyboard component expects, so hopefully turning off
* these "auto" attributes will help.
*/
if (web.isUserAgent("iOS")) {
eTextArea.setAttribute("autocapitalize", "off");
eTextArea.setAttribute("autocorrect", "off");
}
eVideo.appendChild(eTextArea);
/*
* Now we can create the Video object, record it, and wire it up to the associated document elements.
*/
var eContext = eCanvas.getContext("2d");
var video = new Video(parmsVideo, eCanvas, eContext, eTextArea /* || eInput */, eVideo);
/*
* Bind any video-specific controls (eg, the Refresh button). There are no essential controls, however;
* even the "Refresh" button is just a diagnostic tool, to ensure that the screen contents are up-to-date.
*/
Component.bindComponentControls(video, eVideo, APPCLASS);
}
};
/*
* Initialize every Video module on the page.
*/
web.onInit(Video.init);
if (NODE) module.exports = Video;
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