Template matching in C#

Question

I want to get the coordinates(X,Y) of specific image in a web page.After getting that image coordinates I shall move the cursor to this position and click programmatically over this image.

I have saved the image locally I have to compare I will compare this image with the web page and find its location in web page. how is this possible in C#

if this is not possible in C#. Will anybody suggest me any hack in this scenario,

what are you trying to solve? you are giving a solution not a problem. — Vitalik, Apr 25 '11 at 13:20

score 1 · Answer 1 · answered Apr 17 '11 at 11:59

1

Any webpage is client's browser specific. You can't do that in C# since C# is a server language and runs at server and then returns the results in browser specific language. Each client will have different resolution and hence different position for the image. In order to get the coordinates of the image you'll need to use javascript and then move your pointer to that location. You can use jQuery and get image position.

answered Apr 17 '11 at 11:59

Naveed Ahmad

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do jquery support template matching.means i have image which coordinates i want to find in webpage. – Zain Ali Apr 17 '11 at 12:33
Yes, you can give that image an ID or a class name. For example: `var x = $('your-image-id').offset().left; var y = $('your-image-id').offset().top;` – Naveed Ahmad Apr 17 '11 at 12:39

score 1 · Answer 2 · answered Apr 27 '11 at 17:34

1

Template Matching in AForge is done with the ExhaustiveTemplateMatch class:

http://www.aforgenet.com/framework/docs/html/17494328-ef0c-dc83-1bc3-907b7b75039f.htm

But you would first need the screenshot of the browser window to match to.

answered Apr 27 '11 at 17:34

Marino Šimić

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score 0 · Answer 3 · answered Apr 17 '11 at 12:34

As I understand you want to simulate a click event on a browser that displays a page containing your image. If so, you can do somthing like this -

IntPtr lParam = (IntPtr)((y << 16) | x); 
IntPtr wParam = IntPtr.Zero; // Modifier flags - eg ctrl etc 
SendMessage(handle, 0x201, wParam, lParam); // Mouse LBUTTON down
SendMessage(handle, 0x202, wParam, lParam); // Mouse LBUTTON up

handle is target browser window handle, and (x, y) is the location where click is to be simulated - can be the center of your image rect.

no i have stored image locally and i want to find this image location in webpage(template matching). — Zain Ali, Apr 17 '11 at 12:38

score 0 · Answer 4 · edited May 23 '17 at 12:02

I would use plain JavaScript to get the information from the web page.

function getX(/* string */ elementId) {
    return document.getElementById(elementId).offsetLeft;
}

function getY(/* string */ elementId) {
    return document.getElementById(elementId).offsetTop;
}

If you need the position relative to the viewport:

function getX(/* string */ elementId) {
    return document.getElementById(elementId).offsetLeft - document.body.scrollLeft;
}

function getY(/* string */ elementId) {
    return document.getElementById(elementId).offsetTop - document.body.scrollTop;
}

If you need to perform the onClick action on the image without using the mouse:

function clickIt(/* string */ elementId) {
    document.getElementById(elementId).onclick();
}

To invoke JavaScript using C#, you'll need to create a WebBrowser control, load the web page, then invoke the script. You can find how to do that here.

MSDN documentation for HtmlDocument.InvokeScript

Template matching in C#

4 Answers4