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Peter Uhnak

Mar 02, 2015; 10:23pm

roassal pixel rendering

2019 posts

Hi,

I've been experiencing weird behavior with pixel rendering...

basically one pixel lines will get blurred for some reason even though there is no half-pixel overlapping.

Here is a test code (screenshots attached below).

Without the labels the left box will be blurred while the right is better (even though it still has slight shadow); when I add labels however their behavior will switch.

What I would expect is to have nice sharp lines all the time.

Is this Athens issue? Roassal? Pharo?

Its ugly both on Linux and Windows.

====================================

| view box1 box2 |

view := RTView new.

box1 := RTBox new width: 50; height: 51; fillColor: Color transparent; borderColor: Color black; elementOn: '50@51'.

view add: box1.

box2 := RTBox new width: 51; height: 50; fillColor: Color transparent; borderColor: Color black; elementOn: '51@50'.

view add: box2.

"box1 @ RTLabelled.

box2 @ RTLabelled."

box1 translateTo: -50 @ 0.

box2 translateTo: 50 @ 0.

view open

====================================

Peter

without labels.png (1K) Download Attachment

with labels.png (4K) Download Attachment

basilmir

Mar 03, 2015; 8:07am

Re: roassal pixel rendering

64 posts

What is your host system?

If you're on a mac is it Retina?

If you're on windows, what dpi setting are you using?

Pe 3 mar. 2015, la 00:31, Peter Uhnák <[hidden email]> a scris:

> Hi,
>
> I've been experiencing weird behavior with pixel rendering...
>
> basically one pixel lines will get blurred for some reason even though there is no half-pixel overlapping.
>
> Here is a test code (screenshots attached below).
> Without the labels the left box will be blurred while the right is better (even though it still has slight shadow); when I add labels however their behavior will switch.
>
> What I would expect is to have nice sharp lines all the time.
> Is this Athens issue? Roassal? Pharo?
> Its ugly both on Linux and Windows.
>
> ====================================
> | view box1 box2 |
> view := RTView new.
> box1 := RTBox new width: 50; height: 51; fillColor: Color transparent; borderColor: Color black; elementOn: '50@51'.
> view add: box1.
> box2 := RTBox new width: 51; height: 50; fillColor: Color transparent; borderColor: Color black; elementOn: '51@50'.
> view add: box2.
>
> "box1 @ RTLabelled.
> box2 @ RTLabelled."
>
> box1 translateTo: -50 @ 0.
> box2 translateTo: 50 @ 0.
>
> view open
> ====================================
>
> Peter
>
> <without labels.png>
> <with labels.png>

... [show rest of quote]

Peter Uhnak

Mar 03, 2015; 9:54am

Re: roassal pixel rendering

2019 posts

On Tue, Mar 3, 2015 at 9:15 AM, Mircea S. <[hidden email]> wrote:

What is your host system?

If you're on a mac is it Retina?

If you're on windows, what dpi setting are you using?

As I've mentioned, it is both on Linux and Windows (I don't have a mac so I can't test that).

My Linux laptop LCD has 96dpi, and external screen probably higher (I'll check in the evening).

The Windows was another machine, also 96dpi.

However I don't see how that could be DPI related considering with the "correct" size it is rendered correctly.

Peter

Pe 3 mar. 2015, la 00:31, Peter Uhnák <[hidden email]> a scris:

> Hi,
>
> I've been experiencing weird behavior with pixel rendering...
>
> basically one pixel lines will get blurred for some reason even though there is no half-pixel overlapping.
>
> Here is a test code (screenshots attached below).
> Without the labels the left box will be blurred while the right is better (even though it still has slight shadow); when I add labels however their behavior will switch.
>
> What I would expect is to have nice sharp lines all the time.
> Is this Athens issue? Roassal? Pharo?
> Its ugly both on Linux and Windows.
>
> ====================================
> | view box1 box2 |
> view := RTView new.
> box1 := RTBox new width: 50; height: 51; fillColor: Color transparent; borderColor: Color black; elementOn: '50@51'.
> view add: box1.
> box2 := RTBox new width: 51; height: 50; fillColor: Color transparent; borderColor: Color black; elementOn: '51@50'.
> view add: box2.
>
> "box1 @ RTLabelled.
> box2 @ RTLabelled."
>
> box1 translateTo: -50 @ 0.
> box2 translateTo: 50 @ 0.
>
> view open
> ====================================
>
> Peter
>

> <without labels.png>
> <with labels.png>

... [show rest of quote]

HilaireFernandes

Mar 03, 2015; 2:36pm

Re: roassal pixel rendering

1396 posts

In reply to this post by Peter Uhnak

Le 02/03/2015 23:31, Peter Uhnák a écrit :
>
> basically one pixel lines will get blurred for some reason even though
> there is no half-pixel overlapping.
>

I noted the same visual artefact on Dr. Geo with perfectly horizontal 1
pixel width/horizontal line (enclosed zoomed screenshot)

Hilaire

--
Dr. Geo - http://drgeo.eu
iStoa - http://istoa.drgeo.eu

DrGeo-blur.png (8K) Download Attachment

http://drgeo.eu

Nicolai Hess

Mar 03, 2015; 3:15pm

Re: roassal pixel rendering

1347 posts

2015-03-03 15:44 GMT+01:00 Hilaire <[hidden email]>:

Le 02/03/2015 23:31, Peter Uhnák a écrit :
>
> basically one pixel lines will get blurred for some reason even though
> there is no half-pixel overlapping.
>

I noted the same visual artefact on Dr. Geo with perfectly horizontal 1
pixel width/horizontal line (enclosed zoomed screenshot)

with cairo, coordinates are between pixels

-> http://cairographics.org/FAQ/#sharp_lines

Hilaire

--
Dr. Geo - http://drgeo.eu
iStoa - http://istoa.drgeo.eu

Peter Uhnak

Mar 03, 2015; 3:29pm

Re: roassal pixel rendering

2019 posts

with cairo, coordinates are between pixels

-> http://cairographics.org/FAQ/#sharp_lines

Aha! Thank you.

Now the question is how this could be solved. One of their suggestions is use even-integer width, but that from principle wouldn't be true, since it still overlaps by half-a-pixel (so one full and two 1/2 pixels). So the other option is to apply transformation matrix to the whole visualization? So much work for a sharp line. :( And considering that it seems to be blurred in one axis differently than the other... I'll play some more with it.

Pete

abergel

Mar 03, 2015; 6:46pm

Re: roassal pixel rendering

5677 posts

Hi Peter!

I was able to reproduce the problem you describe on Mac.
Indeed, it would be great to have a solution for this.

Thanks for looking into this.

Cheers,
Alexandre

> On Mar 3, 2015, at 10:37 AM, Peter Uhnák <[hidden email]> wrote:
>
> with cairo, coordinates are between pixels
>
> -> http://cairographics.org/FAQ/#sharp_lines
>
> Aha! Thank you.
>
> Now the question is how this could be solved. One of their suggestions is use even-integer width, but that from principle wouldn't be true, since it still overlaps by half-a-pixel (so one full and two 1/2 pixels). So the other option is to apply transformation matrix to the whole visualization? So much work for a sharp line. :( And considering that it seems to be blurred in one axis differently than the other... I'll play some more with it.
>
> Pete
>

... [show rest of quote]

--
_,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:
Alexandre Bergel http://www.bergel.eu
^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;.

abergel

Mar 03, 2015; 6:47pm

Re: roassal pixel rendering

5677 posts

In reply to this post by Peter Uhnak

Added this issue here:
https://code.google.com/p/moose-technology/issues/detail?id=1109

Cheers,
Alexandre

> On Mar 2, 2015, at 5:31 PM, Peter Uhnák <[hidden email]> wrote:
>
> Hi,
>
> I've been experiencing weird behavior with pixel rendering...
>
> basically one pixel lines will get blurred for some reason even though there is no half-pixel overlapping.
>
> Here is a test code (screenshots attached below).
> Without the labels the left box will be blurred while the right is better (even though it still has slight shadow); when I add labels however their behavior will switch.
>
> What I would expect is to have nice sharp lines all the time.
> Is this Athens issue? Roassal? Pharo?
> Its ugly both on Linux and Windows.
>
> ====================================
> | view box1 box2 |
> view := RTView new.
> box1 := RTBox new width: 50; height: 51; fillColor: Color transparent; borderColor: Color black; elementOn: '50@51'.
> view add: box1.
> box2 := RTBox new width: 51; height: 50; fillColor: Color transparent; borderColor: Color black; elementOn: '51@50'.
> view add: box2.
>
> "box1 @ RTLabelled.
> box2 @ RTLabelled."
>
> box1 translateTo: -50 @ 0.
> box2 translateTo: 50 @ 0.
>
> view open
> ====================================
>
> Peter
>
> <without labels.png><with labels.png>

... [show rest of quote]

--
_,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:
Alexandre Bergel http://www.bergel.eu
^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;.

HilaireFernandes

Mar 03, 2015; 7:38pm

Re: roassal pixel rendering

1396 posts

In reply to this post by Nicolai Hess

Le 03/03/2015 16:22, Nicolai Hess a écrit :
> with cairo, coordinates are between pixels
>
> -> http://cairographics.org/FAQ/#sharp_lines
>
Yeah, I guess something like that.

Thanks

Hilaire

--
Dr. Geo - http://drgeo.eu
iStoa - http://istoa.drgeo.eu

http://drgeo.eu