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# Questions tagged [pixel-graphics]

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19 votes
2 answers
17k views

### What is Tessellation in computer graphics

In recent games I have noticed something called Tessellation, Turning the thing ON destroys my frame rate. I have noticed that it when turned on it looks like Anti - Aliasing. Can someone give me ...
• 293
14 votes
2 answers
9k views

### Fast antialiased line drawing

Bresenham's line algorithm is a way of drawing straight lines using only fast integer operations (addition, subtraction, and multiplication by 2). However, it generates aliased lines. Is there a ...
• 1,612
9 votes
3 answers
2k views

### How does a computer upscale 1024x768 resolution to 1920x1080?

Without there being black bars I mean. 1080 isn't any multiple of 768 so is there some sort of data loss?
• 91
8 votes
1 answer
3k views

### Why does checkerboard pattern on a computer screen appear with a yellowish tint?

This question was originally asked on Physics, then moved to Cognitive Sciences. Consider the following image: You might want to display the image in a new page, in case it gets resized for mobile ...
• 183
6 votes
2 answers
2k views

### Difference in pixels between different monitors' sizes

If I have an image of x/y resolution and display it on a monitor, does this mean that between a 15-inch monitor and a 42-inch, the same amount of pixels (x/y) will be displayed, only that each pixel ...
• 161
6 votes
1 answer
544 views

### Anti-aliasing - Controlling colour density of pixel that comes within the "rectangle" surrounding my line

I am currently a beginner when it comes to anti-aliasing. I have read some notes online that how anti-aliasing works is that you first draw the line using an algorithm such as Bresenham's algorithm. ...
• 163
5 votes
2 answers
108 views

### Get screen size and then resize image accordingly

I'm a programmer working in Java and I'm not sure if this is the right place to ask this kind of question, here it goes: In my program, I need to show an image (.jpeg .png etc.) based on the screen ...
• 151
5 votes
1 answer
2k views

### Do GPU performance improve when rendering at native or half resolution, compared to fixed scaling?

This might be an odd question, but I was wondering if you could improve GPU performance with games, comparatively, when using doubles/halves of the native resolution, instead of an odd ratio of that. ...
4 votes
1 answer
105 views

### library / tool for implementing algorithms

I'm new to graphics and want to implement algorithms like dda,scan-line, clipping,etc. I'm confused which library to use. OpenGl, graphics in turbo c,or any other. Please suggest.
• 143
3 votes
1 answer
79 views

### vertical or horizontal line test

I have a line segment defined by two coordinate values and I need to check if the line segment is parallel to the x-axis or y-axis. I believe that it is not that difficult to find. When it comes to ...
• 1,279
3 votes
1 answer
151 views

### human visual: relation of Distance and DPI

I was told that human's visual sharpness is 60 pixels per degree. As such, pixel per inch is approximately given by: PPI = 1/ (Distance * tg((1/60*pi/180) ) Is ...
• 229
3 votes
1 answer
148 views

### What is this technique called and how can I reproduce it algorithmically?

I don't know the name of this technique, but the idea is to adjust the density and location of identical dots or small objects in order to produce a gray tone image or even a suggestion of three ...
• 330
2 votes
3 answers
757 views

### How does the Painter's Algorithm handle transparency?

I was wondering if anyone could explain how the Painter's algorithm would handle transparent objects? Can the Painter's algorithm handle transparency?
• 23
2 votes
2 answers
489 views

### Why do some videos look smoother and others don't on the same monitor

I have a Dell monitor with 60 Hz refresh rate and therefore games playing on it are not very smooth as compared to 120 hz. But when I open videos on YouTube of the same game on the same monitor, some ...
• 123
2 votes
1 answer
2k views

### Thick Line segment

How is this 'wy' equation for thick line segment derived?
2 votes
1 answer
77 views

### Calculate set of rectangles covering pixel diffs?

I'd like to develop a system for web animation similar to animated gifs, like this one. I capture a series of screenshots at fixed time intervals, and then I'd like to animate them. I can trivially ...
• 121
2 votes
0 answers
150 views

### Image Laplacian incomprehension

I am reading and trying to implement a research paper. It uses openGL to define which part of an image to use in order to reconstitute a big image composited of several images. In order to do so, I ...
• 141
1 vote
1 answer
395 views

### Algorithm for thinning a thick line

I'm trying to reduce a thick line, in raster space, down to a thin line, preferably one pixel wide (or thick). Does anybody know of an algorithm that can do this? Imagine you draw with a marker on a ...
• 111
1 vote
1 answer
138 views

### How do I normalize all pixel values such that all pixel values are 'pulled towards' the mean?

Originally asked in Graphic Design site here (but I don't know how to 'move' a question to another site) Credit to this guy: Python Tutorials for Digital Humanities - I followed a lot of his ideas, ...
• 113
1 vote
1 answer
807 views

### Bresenham's Algorithm not drawing horizontal lines

I'm getting started with graphics and I'm having trouble implementing the Bresenham's algorithm. Now, I know that my implementation is incomplente, but I can't see why it doesn't make horizontal lines(...
1 vote
1 answer
1k views

### Which technique is fast to generate real-time reflections?

I want to know about some technique with which i can generate nice reflections on the surface. I know one conventional technique where we invert an object and render it and blend it with the floor but ...
1 vote
2 answers
860 views

### Why does a game at 1080p look better on a 1080p display than 1440p display of the same size

So this is something i recently noticed. I have a 27inch 1440p monitor. And a game in 1080p looks pixelated on that. My friend has a 27 inch 1080p monitor and the same game on 1080p with all same ...
• 111
1 vote
1 answer
132 views

### wall clock using bresenhams circle drawing algo

I am new to CG and I need to draw a wall clock using bresenhams circle algo . I have drawn a circle using this algo but how do I add minute and hour needle in it basically how do i add lines inside a ...
• 11
1 vote
1 answer
3k views

### Convert RGB image to YUV420 using a hlsl shader

I am new to shaders and I need to convert efficiently an RGB image to YUV420. I can convert the RGB image to YUV420 with a simple c++ program that uses the ...
• 11
1 vote
1 answer
101 views

### How to raytrace triangular faces when camera is not at origin?

I've watched the Pixar In A Box, Maths of Rendering Tutorial on Khan Academy. I've started writing a raytracing program and have come to the point where I must solve for ...
1 vote
1 answer
2k views

### How can I draw a filled circle on a grid with the less rectangle as possible?

I have a grid with a variable width/height spacing. Let's say 100 horizontal lines separated by 80 pixels and 100 hundred vertical lines separated by 50 pixels. Each cell of the grid in my logic have ...
• 183
1 vote
0 answers
31 views

### Why refresh rate is needed in a passive-matrix LCD?

In a passive-matrix LCD we have horizontal and vertical conductors. The intersection points are pixels which are cells of liquid crystal molecules . For drawing a frame, we provide the necessary ...
• 111
1 vote
0 answers
313 views

### How can I convert a shape made out of pixels to vertices

I'm trying to implement the solution to get the minimum dissection into rectangles of a rectilinear polygon. My shape is made out of pseudo-pixels (different width/height) but for the moment let's ...
• 183
0 votes
2 answers
116 views

### Purpose and workflow of wireframe models

I am more less familiarized with the major computer graphics concepts up to certain dregree of "low-levelness". So I know how models, vertices, polygons etc. and how these works. Also how is ...
0 votes
1 answer
256 views

### undefined reference to SDL_setRenderDrawColor'

I am getting C:\Users\rasmu\AppData\Local\Temp\ccwOn3mM.o:main.c:(.text+0x11f): undefined reference to SDL_setRenderDrawColor' C:\Users\rasmu\AppData\Local\Temp\ccwOn3mM.o:main.c:(.text+0x155): ...
0 votes
1 answer
16 views

### Clarification on PPI

I wanted to convert a chart rendered by canvas element to an image file so that the user can download it. But the official HTML docs say that: The created image data will have a resolution of 96dpi ...
• 111
0 votes
0 answers
33 views

### What happens when we select lower resolutions on a high-resolution monitor?

I have a monitor with a resolution of 1360x768 (16:9), When I set the resolution to 1280x768 (5:3), 1024x768 (4:3), 800x600 (4:3), even 1920x1080 (16:9) it completely covers the screen and the monitor ...
0 votes
0 answers
29 views

### What APIs are used to output video and audio from a custom codec?

I am looking for tools to generate video and audio output for my own codecs, in my search I found SDL, EGL, FFmpeg and OpenAL, but it is not clear to me if these APIs serve my purpose which is simply ...
• 1
0 votes
0 answers
1k views

### Is it possible to draw horizontal and vertical line with Bresenham's line drawing algorithm?

In computer graphics Bresenham's line drawing algorithm used to draw line . But i want to know the properties why i can't draw vertical and horizontal line by this algorithm.
0 votes
0 answers
491 views

### Sub pixel rendered white text on black background changes color when resized to a very small size

download: https://upload.wikimedia.org/wikipedia/commons/5/57/Subpixel-rendering-RGB.png The above picture is an example for sub pixel rendering. I tried resizing the image to very small size in ...
-1 votes
1 answer
42 views

### Confused about graphic art and what software is used to create the environment of it? [closed]

I have a question that I am stuck on, I am wondering what style is this image considered? And what program do people generally use to create this?