Bug 449471

Summary:	When you rotate the selected sector, the image quality is lost
Product:	[Applications] krita	Reporter:	Plotnikov Pavel <nakoleseg>
Component:	Tools/Transform	Assignee:	Krita Bugs <krita-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	halla
Priority:	NOR
Version First Reported In:	5.0.2
Target Milestone:	---
Platform:	Appimage
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Plotnikov Pavel 2022-02-01 19:26:29 UTC

SUMMARY
***
When you rotate a layer or highlight, the quality of the selected layer is lost. Pixels are not rendered as smoothly as in similar programs, like Paint Tool SAI or Paint Net. In these programs, the line is more accurate. It is often necessary to adjust the angle of inclination of the selected layer or selection, and after rotation it is necessary to redraw..
***


STEPS TO REPRODUCE
1. Open the Krita app
2. Create a new document
3. Select the brush tool (B key)
4. Draw a line
5. Select the rectangular selection tool (Ctrl+R keys)
6. Select a part of the drawn line
7. Select the "transform layer or selection" tool (Ctrl+T keys)
8. Rotate the selected image to an arbitrary angle

OBSERVED RESULT
Image quality is lost when the selected sector is rotated

EXPECTED RESULT:
Preserving the quality of the selected sector during rotation

SOFTWARE/OS VERSIONS
Windows:  - 
macOS:  - 
Linux/KDE Plasma: Zorin OS 15.3 x86_64 
(available in About System)
KDE Plasma Version:  - 
KDE Frameworks Version:  - 
Qt Version: - 

ADDITIONAL INFORMATION
neofetch:
OS: Zorin OS 15.3 x86_64 
Kernel: 5.4.0-96-generic 
Uptime: 1 day, 7 hours, 50 mins 
Packages: 2383 
Shell: bash 4.4.20 
Resolution: 1920x1080 
DE: Xfce 
WM: Xfwm4 
WM Theme: ZorinOrange-Dark 
Theme: ZorinOrange-Dark [GTK2], Zori 
Icons: ZorinOrange-Dark [GTK2], Zori 
Terminal: xfce4-terminal 
Terminal Font: Monospace 12 
CPU: Intel i7 860 (8) @ 2.801GHz 
GPU: AMD Radeon HD 5670/5690/5730 
Memory: 1757MiB / 5905MiB

Comment 1 Plotnikov Pavel 2022-02-01 19:29:45 UTC

SUMMARY
***
When you rotate a layer or highlight, the quality of the selected layer is lost. Pixels are not rendered as smoothly as in similar programs, like Paint Tool SAI or Paint Net. In these programs, the line is more accurate. It is often necessary to adjust the angle of inclination of the selected layer or selection, and after rotation it is necessary to redraw..
***


STEPS TO REPRODUCE
1. Open the Krita app
2. Create a new document
3. Select the brush tool (B key)
4. Draw a line
5. Select the rectangular selection tool (Ctrl+R keys)
6. Select a part of the drawn line
7. Select the "transform layer or selection" tool (Ctrl+T keys)
8. Rotate the selected image to an arbitrary angle

OBSERVED RESULT
Image quality is lost when the selected sector is rotated

EXPECTED RESULT:
Preserving the quality of the selected sector during rotation

SOFTWARE/OS VERSIONS
Windows:  - 
macOS:  - 
Linux/KDE Plasma: Zorin OS 15.3 x86_64 
(available in About System)
KDE Plasma Version:  - 
KDE Frameworks Version:  - 
Qt Version: - 

ADDITIONAL INFORMATION
neofetch:
OS: Zorin OS 15.3 x86_64 
Kernel: 5.4.0-96-generic 
Uptime: 1 day, 7 hours, 50 mins 
Packages: 2383 
Shell: bash 4.4.20 
Resolution: 1920x1080 
DE: Xfce 
WM: Xfwm4 
WM Theme: ZorinOrange-Dark 
Theme: ZorinOrange-Dark [GTK2], Zori 
Icons: ZorinOrange-Dark [GTK2], Zori 
Terminal: xfce4-terminal 
Terminal Font: Monospace 12 
CPU: Intel i7 860 (8) @ 2.801GHz 
GPU: AMD Radeon HD 5670/5690/5730 
Memory: 1757MiB / 5905MiB

Comment 2 Halla Rempt 2022-03-08 09:58:40 UTC

You can select a different interpolotation method in the transform tool's option widget. However, rotating pixels is and will always be lossy, since there will be interpolation.