How do I create pixel accurate graphics?

Use exact positioning and widths, and on exporting pay attention to exporting dpi and other values.

This is exactly what I have been trying to do and I keep on getting the lines appearing in the incorrect pixel position, and also sometimes the lines are 1 pixel wide, sometimes 2 pixel wide.

Maybe there is something subtle I am doing wrong. Here are my steps.

Lets say I want a 100x100 bitmap with a 1 pixel square outline from 5,5 to 95,95.
1. I create a new document, go to 'Document Properties' and set Width and Height to 100 px, and 'Default Units' to px
2. I select the rectangle tool and draw a square of approximately the right size
3. I click on the "Select and Transform Objects" Tool (i.e. cursor pointer) to get access to the X, Y, W, and H parameters
4. I enter "X:5.000 Y: 5.000 W: 90.000 H: 90.000"
5. I open up "Fill and Stroke" properties and set Fill to none, Stroke Paint to solid black, and Stroke Style to solid 1.000px, square cap and join, 0% blur, 100% opacity

By this time, if I look back at the dimensions of the rectangle I created, instead of showing "X:5.000 Y: 5.000 W: 90.000 H: 90.000" like I have configured it, it has already changed on its own to "X:5.007 Y: 5.007 W: 89.986 H: 97.486", so I go back and set it again to "X:5.000 Y: 5.000 W: 90.000 H: 90.000"

6. I go to File/Export Bitmap, select 'Page', make sure that the source region is (0.000,0.000) to (100.000,100.000), set my bitmap size to 100x100 pixels, which gives me 90.00dpi, enter file name and export.

As a result I get a PNG file that has lines as follows (assuming coordinates start with 0,0 at top left):
1. a 2 pixel wide translucent (grayish) horizontal line from (5,7) to (94,8),
2. a solid 1 pixel wide horizontal line from (5,94) to (94,94), and
3. 2 solid vertical 1 pixel wide lines: (5,9) to (5,94) and (94,9) to (94,94)

I go back to the drawing and discover that the rectangle has once again changed its height on me to 87.486.

I would greatly appreciate someone helping me figure this out.

Thank You,
Marcin

Performing 1-5 and then checking the placement and dimensions doesn't have any effect on those properties for me (Inkscape 0.46+devel, built Apr 6 2008; on Kubuntu Intrepid (8.10)).

Export is as expected and checking in GIMP I have exact same rendering in inkscape's-output raster as I do in GIMP's import of the SVG. No blurry lines or anything.

You should file this as a bug report, it doesn't seem to be just a question. Then also post your inkscape file and output raster for comparison.

Bounding box by default (see preferences) is calculated not from line but
from stroke, so changing stroke width changes bounding box size. What the
second change is about, I don't know.
And the same for me, it works well giving expected results with no gray at
all.

Beautiful!

Marcel, setting up the grid worked like a charm.

Thank You,
Marcin

Thanks marcel, that solved my question.

It's still weird to me that I followed your instructions and it worked fine ...

pbhj, as I mentioned above the bounding box calculations (and therefore the width/height and position) are adjustable from preferences. If you set the bounding box to line (as opposed to stroke), it may behave different.

Hello,

The new title is wrong for this question. My question had nothing to
do with dpi setting, but was referring to creating whole-pixel
accurate graphics. Please change the title (or 'summary') of this
question back to what it was.

Thank You,
Marcin

On 2009-May-15, at 0:38 , sionpatho wrote:

> Your question #52283 on Inkscape changed:
> https://answers.launchpad.net/inkscape/+question/52283
>
> Summary changed to:
> how do i increase the dpi from 72 to 300 in the existing diagram
> without pixelation
>
> --
> You received this question notification because you are a direct
> subscriber of the question.

Creating pixel-accurate graphics involves paying meticulous attention to detail and precision. Here's a step-by-step guide to help you achieve pixel perfection:

Use a Grid System:

Set up a grid in your design software with each grid cell representing a pixel. This will act as a guide for placing elements precisely.
Adjust the grid settings to match the pixel dimensions you're working with. https://www.pixelscalculator.com/pixels-to-mm/
Zoom In:

Zoom in on your canvas to a high magnification level. This allows you to see individual pixels clearly and make accurate adjustments.
Snap to Pixel:

Enable the "snap to pixel" or "snap to grid" option in your design software. This ensures that your elements align with the pixel grid, preventing blurry or distorted edges.
Use Whole Numbers:

Position objects and elements at whole pixel values (e.g., x=10, y=20) rather than fractional values. This helps maintain crisp edges and prevents anti-aliasing.
Manual Editing:

Manually edit and adjust each pixel if necessary. This may involve using tools like the pencil or brush tool to place pixels precisely where needed.
Color Palette:

Limit your color palette to maintain clarity. Stick to a reduced set of colors that are easily distinguishable and fit the overall aesthetic.
Anti-Aliasing Awareness:

Be mindful of anti-aliasing, especially when working with text. Turn off anti-aliasing or use it sparingly to avoid softening the edges of your graphics.
Test at Actual Size:

Regularly test your graphics at actual size to ensure that they look as intended. Viewing at a smaller scale may hide imperfections that become noticeable at the intended size.
Save in the Correct Format:

Choose the appropriate file format for pixel art. Formats like PNG or GIF with a limited color palette are often preferred for pixel graphics.
Iterate and Refine:

Review your work regularly and make incremental adjustments. Pixel art often involves a process of refining and tweaking to achieve the desired level of precision.
Seek Feedback:

Share your work with others, especially those experienced in pixel art, to get feedback. Fresh eyes may catch details that you might have overlooked.
Remember, pixel art is a craft that benefits from patience and attention to detail. Practice, experimentation, and a keen eye for detail will contribute to improving your ability to create pixel-accurate graphics over time.