Ofsaveframe() resolution

[bbq]

Hi all, my monitor is 2880 x 1800. ofsaveframe() is really convenient, but it saves images at exactly half of this resolution. Is there any way around this?

[moebiussurfing]

hey, can you show the code you are using?

here you have a little code to capture a frame:

OF_FULLSCREEN screenshots fail on Windows - fix?

hey @Drazinut, EDIT: sorry, I think I misunderstood your problem… That seems the same that you are doing. you can get more info on the key events like this: (and then to save the screenshot like that or using another faster-threaded method) //-------------------------------------------------------------- //void ofApp::keyPressed(int key) { void ofApp::keyPressed(ofKeyEventArgs &eventArgs) { const int key = eventArgs.key; const int keycode = eventArgs.keycode; const int scancode = eventArg…

[moebiussurfing]

//take screenshot
		{
			ofImage img;
			img.grabScreen(0, 0, ofGetWidth(), ofGetHeight());
			string _pathFolder = "captures/";
			string _fileName = "snapshot_" + ofGetTimestampString() + ".png";
			string _pathFilename = ofToDataPath(_pathFolder + _fileName, true);//bin/data
			bool b = img.save(_pathFilename);
			if (b) cout << __FUNCTION__ << " Saved screenshot successfully: " << _pathFilename << endl;
			else cout << __FUNCTION__ << " Error saving screenshot:" << _pathFilename << endl;
		}

[bbq]

ofImage img; img.grabScreen(0, 0, ofGetWidth(), ofGetHeight()); string _pathFolder = “captures/”; string fileName = "snapshot" + ofGetTimestampString() + “.png”; string _pathFilename = ofToDataPath(_pathFolder + _fileName, true);//bin/data bool b = img.save(_pathFilename);

Ah… this is good, but has the same issue as simply using ofSaveFrame(). If I use ofGetWidth()/ofGetWidthHeight() and run my app at full screen it takes the screenshot at half the resolution of my monitor. If I manually enter the resolution it takes the screenshot at the correct dimensions it only fills a portion of it.

[Drazinut]

Huh. FWIW, mine produces full-size screenshots, but my monitor is only 1920x1080… hmm.

At least, on Windows. What OS are you seeing this problem on?

[bbq]

Mac

[Drazinut]

Ok, then I think it is because it is a Retina display, and OF (at least by default) running at half the Retina resolution.

This thread might provide the answer:

Image processing at Retina density

I’m using a Mac with a Retina screen. I’m trying to process a bunch of images using OpenGL shaders and save them. I create a 100x100 window, load my image, run it through the OpenGL shader, and save it to disk using ofPixels img; img.grabScreen(0, 0 , ofGetWidth(), ofGetHeight()); img.save("screenshot-" + to_string(frame) + ".png"); The output is a 100 x 100px image, as expected. However, if I take a screenshot manually, I get a 200x200 px image saved, which I understand is due to my Retina s…

other related threads:

Resolution in gl context doesn't fit with ofGetWidth()?

Hi OF community ! I just need some clarification about this ? I see in “about this mac” that my screen has 2880/1800 pixels resolution. I set in main.cpp -> ofSetupOpenGL(1920,1080,OF_FULLSCREEN); when I call ofGetWidth() in ofApp::setup(), I cannot get value higher than 1680/951 ? I was expecting to get 1920/1080. when I call ofGetScreenWidth() / Height(), I get 1680/1050 ? here I was expecting 2880/1800. What am I missing ? or maybe someone can point me to documentation that explain t…

Retina/High Resolution Capable/HiDPI example?

I’ll switch to the nightly build and see if there are any issues, though it’s sounds like I’ll be fine. Any idea when the next release (0.11.1??) is due? Thanks for you help!

[bbq]

Thank you so much, enabling high resolution in the .plist file did the trick!

[bbq]

Unfortunately, it is still not exactly the same as taking a screenshot manually. The dimensions are correct but the “resolution” (not sure how that’s different, technically) is still halved. This causes issues when I compile the frames into a video, despite the screenshots being apparently indistinguishable.

After compiling to video (using quicktime) there is this issue: . It should be perfectly straight but the border is blurred. I suspect this is caused by the halved resolution.

Manual screenshot compiled to video with perfectly straight borders:

[Drazinut]

Oh, huh “resolution” 72x72 would seem to mean something is thinking resolution for printing is relevant to your screenshot - i.e. 72 dpi dots per INCH so I imagine something is trying to be helpful by compressing and/or discarding image data higher than that precision.