I noticed that at certain zoom levels the pixel grid is rendered unevenly. This gives the image a 'speckled' appearance as if it had light grey dots all over it.
The effect is easily seen when using Ctrl+Scroll on the mouse wheel to zoom.
Attached is a zoomed version of the problem, at a zoom level around 480%.
I noticed this with and without hardware acceleration.
To reproduce:
1. Start with new image (white background) and pixel grid enabled
2. Ctrl+Scroll mouse until around 400%-500% zoom (I was at 448% but visible at other zoom levels)
--> pixel grid has speckled appearance
Issues/Expectations
It seems that there are a few issues that cause this effect:
1. when two pixel grid lines overlap they get darker
-> expected: pixel grid should have a uniform color
2. adjacent pixel grid lines do not necessarily have their pixels in the same position, causing a seemingly random (Moiré-like) pattern
-> expected: pixels in adjacent lines should line up
3. the pixel grid spacing varies, probably due to rounding. The attached example shows a spacing of either every 4 or 5 pixels.
-> expected: hard to avoid. perhaps a different zoom mode that only allows zoom levels that result in a uniform pixel size?
Otherwise, perhaps solid lines could be used below a certain zoom level to avoid the dotted line Moiré effect.
Diagnostics
Application paint.net 4.0.21 (Final 4.21.6589.7045)
Build Date Montag, 15. Januar 2018
Install type Classic
Hardware accelerated rendering (GPU) True
Animations True
DPI 96,00 (1,00x scale)
Language en-US
OS Windows 7 Enterprise Service Pack 1 x64 (6.1.7601.65536) (0x4)
.NET Runtime 4.0.30319.42000
Physical Memory 16.263 MB
CPU Intel(R) Core(TM) i7-6820HQ CPU @ 2.70GHz
Speed ~2712 MHz
Cores / Threads 4 / 8
Features DEP, SSE, SSE2, SSE3, SSSE3, SSE4_1, SSE4_2, XSAVE
Video Card NVIDIA Quadro M2000M
Dedicated Video RAM 4.034 MB
Dedicated System RAM 0 MB
Shared System RAM 7.875 MB
Vendor ID 0x10DE
Device ID 0x13B0
Subsystem ID 0x80D5103C
Revision 162
LUID 0x0001CBCC
Flags None
Outputs 2
Video Card Intel(R) HD Graphics 530
Dedicated Video RAM 192 MB
Dedicated System RAM 0 MB
Shared System RAM 1.632 MB
Vendor ID 0x8086
Device ID 0x191B
Subsystem ID 0x80D5103C
Revision 6
LUID 0x0001CEE3
Flags None
Outputs 0