Locating Pixels with Bresenham's line algorithm

[armin11]

hi,I wanted to locate the pixels of a line drawn from (0,0) to (-4,-8) with bresenham's algorithm.I couldn't find a suitable algorithm for finding these pixel locations.Can anyone help me please?(the algorithm can be without computer and work by hand)

 

[Bill Simpson]

A very powerful secret method of finding excellent information: Google
wiki <<<brief clear name of what you are looking for>>>

Example
http://www.google.com/search?q=wiki+bresenham's+algorithm

 

[armin11]

I've searched so much and tried every algorithm they have written ,but they don't work.can anybody help please?

 

[Grep]

This smells like a homework question... In which case you're in the wrong forum.

Also not a hard one. The wiki has full (and rather simple) pseudocode for Bresenham's. Can you really not turn that into working code? That's all you need to do.

 

[LudusRex]

Bresenham's line algorithm is a commonly used method for drawing lines on a computer screen. It works by calculating the coordinates of pixels that lie on the line between two specified points. While this algorithm is typically used in computer graphics, it can also be applied by hand.

To locate the pixels of a line drawn from (0,0) to (-4,-8), we can follow these steps:

1. Calculate the slope of the line using the formula: m = (y2-y1)/(x2-x1). In this case, m = (-8-0)/(-4-0) = 2.

2. Determine the major axis of the line. This is the axis with the larger absolute change in coordinates. In this case, the major axis is the y-axis.

3. Starting from the first point (0,0), we can plot the first pixel on the y-axis (since it is the major axis) and mark it as (0,0).

4. Next, we can use the slope to determine the next pixel on the line. In this case, for every change of 1 unit on the major axis (y-axis), the minor axis (x-axis) changes by 1/2 unit (since m=2). Therefore, we can plot the next pixel at (0,1).

5. We repeat this process, moving 1 unit on the major axis and 1/2 unit on the minor axis, until we reach the end point (-4,-8).

6. The pixels that lie on the line between (0,0) and (-4,-8) are: (0,0), (0,1), (-1,2), (-1,3), (-2,4), (-2,5), (-3,6), (-3,7), and (-4,8).

I hope this helps you locate the pixels using Bresenham's algorithm without a computer. Please let me know if you have any further questions.