Is there a cross-platform approach to taking screenshots from a firefox extension?
Ideally I'd like to be able to take a screenshot of a dom element (irrespective of whether it's visible on the page or not), something like:
var screenshot = screenshot(document.getElementById('example');
Any pointers or suggestions would be nice, searching https://developer.mozilla.org/ only yields screenshots they've used in various guides.
After examining the code of several extensions. I took the following approach (to take a snapshot of a particular dom element). This can be used in a Firefox extension to take screenshots of the whole page, to take screenshots of the browser window and to take screenshots of a particular dom element (and all of its child nodes):
Add canvas to xul.
Find dimensions and top-left co-ordinates of element.
Copy portion of window to canvas.
Convert canvas to base64 PNG file.
function getElementScreenshot(elm) {
var x = findPosX(elm);
var y = findPosY(elm);
var width = elm.clientWidth;
var height = elm.clientHeight;
var cnvs = document.getElementById("aCanvas");
cnvs.width = width;
cnvs.height = height;
var ctx = cnvs.getContext("2d");
// To take a snapshot of entire window
// ctx.drawWindow(mainWindow.content, 0, 0, mainWindow.innerWidth, mainWindow.innerHeight, "rgb(255,255,255)");
ctx.drawWindow(mainWindow.content, x, y, width, height, "rgb(255,255,255)");
return(cnvs.toDataURL());
}
To find top left coordinate of an element
function findPosX(obj) {
var curleft = 0;
if (obj.offsetParent) {
while (1) {
curleft += obj.offsetLeft;
if (!obj.offsetParent) {
break;
}
obj = obj.offsetParent;
}
} else if (obj.x) {
curleft += obj.x;
}
return curleft;
}
function findPosY(obj) {
var curtop = 0;
if (obj.offsetParent) {
while (1) {
curtop += obj.offsetTop;
if (!obj.offsetParent) {
break;
}
obj = obj.offsetParent;
}
} else if (obj.y) {
curtop += obj.y;
}
return curtop;
}
To get access to browser.xul from sidebar
var mainWindow = window.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
.getInterface(Components.interfaces.nsIWebNavigation)
.QueryInterface(Components.interfaces.nsIDocShellTreeItem)
.rootTreeItem
.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
.getInterface(Components.interfaces.nsIDOMWindow);
mainWindow.gBrowser.addTab(...);
Download one of the many Firefox screen capture extensions, and look at their code to see how they do it. Eg Screengrab, Fireshot, or Page Saver
I guess it would be something like this:
Copy the DOM element in question to a separate iframe or browser (which is not visible to the user)
Paint the window of that iframe onto an html canvas using drawWindow(). Check out the source of the Tab Preview addon to see how this is done.
Related
Right, parsing the clipboard, I am trying to detect if a stored bitmap in there might be the result of a screenshot the user took.
Everything is working fine as long as the user only has one monitor. Things become a bit more involved with two or more.
I am using the routing below to grab all the displays in use. Now, since I have no idea how they are configured to hang together, I do not know how to calculate the size of the screenshot (that Windows would produce) from that information.
I explicitly do not want to take a screenshot myself to compare. It's a privacy promise by my app.
Any ideas?
Here is the code for the size extractor, run in the UI thread.
public static async Task<Windows.Graphics.SizeInt32[]> GetMonitorSizesAsync()
{
Windows.Graphics.SizeInt32[] result = null;
var selector = DisplayMonitor.GetDeviceSelector();
var devices = await DeviceInformation.FindAllAsync(selector);
if (devices?.Count > 0)
{
result = new Windows.Graphics.SizeInt32[devices.Count];
int i = 0;
foreach (var device in devices)
{
var monitor = await DisplayMonitor.FromInterfaceIdAsync(device.Id);
result[i++] = monitor.NativeResolutionInRawPixels;
}
}
return result;
}
Base on Raymonds comment, here is my current solution in release code...
IN_UI_THREAD is a convenience property to see if the code executes in the UI thread,
public static Windows.Foundation.Size GetDesktopSize()
{
Int32 desktopWidth = 0;
Int32 desktopHeight = 0;
if (IN_UI_THREAD)
{
var regions = Windows.UI.ViewManagement.ApplicationView.GetForCurrentView()?.WindowingEnvironment?.GetDisplayRegions()?.Where(r => r.IsVisible);
if (regions?.Count() > 0)
{
// Get grab the most left and the most right point.
var MostLeft = regions.Min(r => r.WorkAreaOffset.X);
var MostTop = regions.Min(r => r.WorkAreaOffset.Y);
// The width is the distance between the most left and the most right point
desktopWidth = (int)regions.Max(r => r.WorkAreaOffset.X + r.WorkAreaSize.Width - MostLeft);
// Same for height
desktopHeight = (int)regions.Max(r => r.WorkAreaOffset.Y + r.WorkAreaSize.Height - MostTop);
}
}
return new Windows.Foundation.Size(desktopWidth, desktopHeight);
}
I'm trying to insert images into Google Docs (other GSuite apps later) from an Add-On. I've succeeded in fetching the image and inserting it when getCursor() returns a valid Position. When there is a selection (instead of a Cursor), I can succeed if it's text that's selected by walking up to the Parent of the selected text and inserting the image at the start of the paragraph (not perfect, but OK).
UPDATE: It seems that I was using a deprecated method (getSelectedElements()), but that didn't fix the issue. It seems the issue is only with wrapped images as well (I didn't realize that the type of the object changed when you changed it to a wrapped text).
However, when an wrapped-text Image (presumably a PositionedImage) is highlighted (with the rotate and resize handles visible in blue), both getSelection() and getCursor() return null. This is a problem as I would like to be able to get that image and replace it with the one I'm inserting.
Here's my code... any help would be great.
var response = UrlFetchApp.fetch(imageTokenURL);
var selection = DocumentApp.getActiveDocument().getSelection();
if (selection)
{
Logger.log("Got Selection");
var replaced = false;
var elements = selection.getRangeElements();
if (elements.length === 1
&& elements[0].getElement().getType() === DocumentApp.ElementType.INLINE_IMAGE)
{
//replace the URL -- this never happens
}
//otherwise, we take the first element and work from there:
var firstElem = elements[0].getElement();
Logger.log("First Element Type = " + firstElem.getType());
if (firstElem.getType() == DocumentApp.ElementType.PARAGRAPH)
{
var newImage = firstElem.asParagraph().insertInlineImage(0, response);
newImage.setHeight(200);
newImage.setWidth(200);
}
else if (firstElem.getType() == DocumentApp.ElementType.TEXT)
{
var p = firstElem.getParent();
if (p.getType() == DocumentApp.ElementType.PARAGRAPH)
{
var index = p.asParagraph().getChildIndex(firstElem);
var newImage = p.asParagraph().insertInlineImage(index, response);
newImage.setHeight(200);
newImage.setWidth(200);
}
}
} else {
Logger.log("Checking Cursor");
var cursor = DocumentApp.getActiveDocument().getCursor();
if (cursor)
{
Logger.log("Got Cursor: " + cursor);
var newImage = cursor.insertInlineImage(response);
var p = cursor.getElement();
var size=200;
newImage.setHeight(size);
newImage.setWidth(size);
}
}
You are using the deprecated 'getSelectedElements()' method of the Range class. You may notice it's crossed out in the autocomplete selection box.
Instead, use the 'getRangeElements()' method. After selecting the image in the doc, the code below worked for me:
var range = doc.getSelection();
var element = range.getRangeElements()[0].getElement();
Logger.log(element.getType() == DocumentApp.ElementType.INLINE_IMAGE); //logs 'true'
I am making a webpage with a "time line" style, it's navigated horizontally but has a fixed menu with an element that slides along a bar when you click on every element.
Now I was using a blueprint of vertical timeline that also moved the element across the bar when you got to the element by scrolling normally
http://www.webdesigncrowd.com/demo/slider-timeline-menu-12.2.13/
Now, I am using a page-wrap div to keep the elements within a certain boundary along with a css style for the body to stack elements horizontally.
When I click on ever it takes me to the correct page like normal, and the bar element works as intended, but the feature for it to work when the linked element moves into view doesn't seem to work anymore
This is the original JS code
// Scroll Spy
$(window).scroll(function() {
var top = $(window).scrollTop() + 100; // Take into account height of fixed menu
$(".container").each(function() {
var c_top = $(this).offset().top;
var c_bot = c_top + $(this).height();
var hash = $(this).attr("id");
var li_tag = $('a[href$="' + hash + '"]').parent();
if ((top > c_top) && (top < c_bot)) {
if (li_tag.hasClass("active")) {
return false;
} else {
li_tag.siblings().andSelf().removeClass("active");
li_tag.addClass("active");
$(".menu ul li.active a").slideToPos();
}
}
});
});
And this is what I edited to try to make it work on a Horizontal display.
// Scroll Spy
$(window).scroll(function() {
var left = $(window).scrollLeft() + 1300; // Take into account height of fixed menu
$(".container").each(function() {
var c_Left = $(this).offset().left;
var c_bot = c_left + $(this).width();
var hash = $(this).attr("id");
var li_tag = $('a[href$="' + hash + '"]').parent();
if ((left > c_Left) && (left < c_bot)) {
if (li_tag.hasClass("active")) {
return false;
} else {
li_tag.siblings().andSelf().removeClass("active");
li_tag.addClass("active");
$(".menu ul li.active a .navut").slideToPos();
}
}
});
});
Now I have tried using the original one without change too, but that feature is still not working.
I thank you guys in advance.
this is a post I have made on the adobe forum...
I'm newish to flash and i'm doing a presentation as part of a University assignment.
My problem is basically this. As part of my presentation I have a photo gallery which uses thumbnail images as buttons and then a UI loader to load a pop up version of the larger image from my webserver - as per https://www.youtube.com/watch?v=Peo_nT9HHa0
The image was created on photoshop. It is a .jpg and has text within the image that describes underneath it what the image is all about. The text within photoshop is set to anti-aliasing 'smooth' and when I test the movie within flash, the text underneath the image looks fine - just as it does in photoshop.
However, when I publish and upload the .swf file to my webserver and view the image through a browser, the text looks awful - all jaggy and broken if that makes sense.
Any ideas why?
I was given a reply of...
If you are loading the images dynamically then you will have to set the smoothing property true after the file(s) has been loaded. So if you don't currently have a listener for the images finishing loading, you will need one, and an event handler function to assign the smoothing property to true for each of them.
Can anyone help with creating the actionscript for this listener and event handler function?
I basically have a gallery movie clip with buttons that act as clickable thumbnails. The actionscript for that is...
btnImage1.addEventListener(MouseEvent.CLICK, loadimage1);
function loadimage1 (event:MouseEvent):void{
imagetxt.text = "a";
togglewindow.gotoAndPlay(2)
}
and then a UI loader that displays the larger image when a thumbnail is clicked
if (MovieClip(this.parent).imagetxt.text == "a"){
var imgurl:String ="IMAGE URL";
var myrequest:URLRequest = new URLRequest(imgurl);
myloader.load(myrequest);
}
As indicated, you should always turn smoothing on if the image is going to be scaled at all. It uses a different scaling algorithm that blurs pixels rather than deletes them. Take note that it is substantially slower to smooth, but on modern machines you shouldn't notice the difference unless you are doing it to thousands of images all at once.
After instantiation, add a Event.COMPLETE handler to Loader.contentLoaderInfo.
var myLoader = new Loader();
myLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, loaderCompleteHandler);
Then in the handler, you can access the Bitmap and turn smoothing on.
function loaderCompleteHandler(e:Event):void {
var image:Bitmap = myLoader.content as Bitmap; //Loader.content is typed as a DisplayObject, so we need to cast it as a Bitmap
image.smoothing = true;
}
And that should solve the issue. You may need to add the image object to the stage rather than the myLoader object. I don't think you'll have to, but I can't remember.
Just add event an event listener to your loader. Like this:
load.addEventListener(Event.COMPLETE,doneLoad);
then in the doneLoad function get the event.data and cast it to Bitmap and set the bitmap smoothing to true:
var myBitmap:Bitmap= e.target.data as Bitmap;
myBitmap.smoothing=true;
//add bitmap to parent ....
I wrote you universal method for loading images, you should pass 3 arguments to the method: holder for big images, image path, and rectangle to restrict image bounds and resize them. This method should be sufficient for your task.
private function loadImage(holder:DisplayObjectContainer, path:String, bounds:Rectangle):void {
var loader:Loader = new Loader();
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, function (e:Event):void {
var bitmap:Bitmap = loader.content as Bitmap;
if (bitmap != null) {
bitmap.smoothing = true;
//Resize bitmap to fit bounds
var availableRatio:Number = bounds.width / bounds.height;
var componentRatio:Number = bitmap.width / bitmap.height;
if (componentRatio > availableRatio) {
bitmap.width = bounds.width;
bitmap.height = bounds.width / componentRatio;
} else {
bitmap.width = bounds.height * componentRatio;
bitmap.height = bounds.height;
}
//Clear previous
var i:uint, len: uint = holder.numChildren, old: Bitmap;
for(i; i < len; ++i){
old = holder.removeChildAt(0) as Bitmap;
old.bitmapData.dispose();
}
//Here you can add some appear animation
bitmap.x = bounds.x + ((bounds.width - bitmap.width) >> 1);
bitmap.y = bounds.y + ((bounds.height - bitmap.height) >> 1);
holder.addChild(bitmap);
}
});
loader.load(new URLRequest(path));
}
Usage:
loadImage(myContainer, "Path-to-Image", new Rectangle(20, 20, 400, 200));
This section of code in my /js/global.js file activate each image to open in a new window when clicked. Is it possible to alter this code to have each open in a FancyBox instead? I have downloaded a FancyBox plugin for a Vanilla forum I am running, and it currently only targets images embedded in posts After You Click On The Post Itself. On the main page, clicking on an image opens a new window.
// Shrink large images to fit into message space, and pop into new window when clicked.
// This needs to happen in onload because otherwise the image sizes are not yet known.
jQuery(window).load(function() {
var props = ['Width', 'Height'], prop;
while (prop = props.pop()) {
(function (natural, prop) {
jQuery.fn[natural] = (natural in new Image()) ?
function () {
return this[0][natural];
} :
function () {
var
node = this[0],
img,
value;
if (node.tagName.toLowerCase() === 'img') {
img = new Image();
img.src = node.src,
value = img[prop];
}
return value;
};
}('natural' + prop, prop.toLowerCase()));
}
jQuery('div.Message img').each(function(i,img) {
var img = jQuery(img);
var container = img.closest('div.Message');
if (img.naturalWidth() > container.width() && container.width() > 0) {
img.wrap('');
}
});
// Let the world know we're done here
jQuery(window).trigger('ImagesResized');
});
Add an specific class to your wrapped images, modifying this line
img.wrap('');
... into this :
img.wrap('<a class="fancybox" href="'+$(img).attr('src')+'"></a>');
Then bind fancybox to that selector (".fancybox") in a custom script like :
$(".fancybox").fancybox();
This assumes that you have properly loaded the fancybox js and css files.