Java: set screen pixel color directly? - java

I have searched for an answer for this question, but all attempts have proven no useful info.
I am trying to figure out a way to draw a pixel directly to the screen, without using a fullscreen canvas of sorts.
Is there any way to do this? If so, what is the best (And/Or most efficient) way to do so?
Thanks in advance.
EDIT: For those who are confused, I am trying to draw directly to the screen, without a fullscreen canvas. I want to set a pixel color on the screen if you will, sort of like drawing to the video hardware.

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How do I make 2d- Flashlight effect in Processing 3

For reference the effect I'm going for is this:
I'm working in Processing 3, NOT p5.js.
I've looked around processing forums, but i can't find anything that works in the current version or doesn't use PGraphics and a mask which from what I've read can be expensive to use.
My current ideas and implementations have resulted to drawing shapes around the player and filling the gaps in with a circles with no fill that has a large stroke weight.
Does anyone know of any methods to easily and inexpensively draw a black background over everything except a small circular area?
If this is the wrong place to ask this question just send me on my way I guess, but please be nice. Thank you:)
You could create an image (or PGraphics) that consists of mostly black, with a transparent circle in it. This is called image masking or alpha compositing. Doing a Google image search for "alpha composite" returns a bunch of the images I'm talking about.
Anyway, after you have the image, it's just a matter of drawing it on top of your scene wherever the player is. You might also use the PImage#mask() function. More info can be found in the reference.

How to paint the portion of the image inside its border line via using libgdx?

I am creating an image painting app in libgdx where user would touch the portion of the image. e.g If the user touch the wheels of a car that should turn into the selected color.
I don't really know how to specify the custom area around the touch. That can be a wheel, a door which are not always rectangle and circle. I just need an idea to do it. Whether libgdx pixelmap can achive this. I have to paint the image inside the border line of the touch region. I hope my problem is clearly stated.
I woule really appreciate for your time for giving the answers. Thanks in advance
I think you want to look at flood fill algorithms. I don't think there is any built-in support for this in libGDX, but you should be able to implement your own flood fill on a libGDX pixmap.

Best way to render and update an image each frame?

What is the best way to edit singular pixels of an texture multiple times per frame? I have tried using a couple ways to no avail. What is the most optimal way to do this? I have tried using Intermediate mode and drawing each quad, thought, this is really slow.
Edit:
I forgot to mention that I am doing an unusual "fog of war" system. This system doesn't let you see around walls but instead acts like a 2D ray traced shadow. I want these shadows to be pixelated as this is part of the style of the game. I am trying to find the best way to do a form of a shadow map that I can overlay over the world to show what you can see.
I recommend using a Pixel Buffer Object.

Canvas vs Image Android

I have a background image that is white and semi-transparent. This is used as a text container so you can differentiate between the background image and text.
Currently I am using an image that is a white rectangle with rounded corners, but of course when using this on different screen sizes the image is distorted, not massively or that noticeably, but would it be better or possible to draw this image with a canvas?
If it is possible would it slow down the app considerably?
UPDATE:
Thank you #jkhouw1 I have looked into 9 patch images and this seems very suitable. I am still interested in knowing the benefit of canvas against images, but if you post something as an answer I will accept it. Thank you.
use a nine patch is a graphic that android can scale appropriately. see here: http://developer.android.com/guide/developing/tools/draw9patch.html
and here http://www.higherpass.com/Android/Tutorials/Android-9-Patch-Scaled-Png-Image-Guide/
Haven't tried this yet, but I think this should be possible by defining a shape drawable. You can define round corners and you can make it semi-transparent by defining the color with alpha-value, for example #80FF0000 should be semi-transparent red.
I assume this would be a good solution both in terms of compatibility and performance.

mouseListeners and JLabels using images with transparent pixels

I'm willing to make a isometric game but I'm having hard time with the mouseListener.
I'm using Swing and make losanges by using square images with transparent pixels (GIF format).
The problem is that making losanges touch each other edge means having the transparent pixels of one on the top of the others, which is a problem with the mouseListener.
I'm willing to know exactly which losange was clicked on, but as the transparent pixels of the nearby losange get on the top of the one that was clicked on, the wrong losange is selected as the KeyEvent source.
Is there a way to have mouseListener not considering transparent pixels as part of the shape ?
Thanks for reading.
It's not clear
1) why the tiles have to overlap, or
2) why you're using JLabels for the tiles
There's are many ways to solve the problem you're having, but I'd just make a single JComponent that renders the tiles as needed, and is the sole MouseListener.
As mentioned by Jonathan, I think you're using the wrong technology for the job. I've had great success using a 2D graphics framework for software such as this. In my case I'm a big fan of Piccolo. I know you don't want to hear this, but consider starting over with the appropriate toolset.

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