WPF Font Scaling Problem with Render Target Bitmap at Format1bppIndexed

[vsfeedback]

I am using .Net framework 4.6.1 and faced following scaling problem in Arial Font.

Below image is generated with same program at DPI 96 for [100% windows 10 Scaling] and

DPI 120 for [125% recommended windows 10 Scaling]

In the result we can clearly see non homogeneity in rendering

I am also attaching project file,

You can experience same with program and executable (Its based on Arial Font)
Steps to reproduce:
Drag/move canvas elements on left and you will see Format1bppIndexed Image

image generated on left side.

All I want is to have homogeneous and smooth text rendering under different windows 10 scaling when rendering target bitmap @ Format1bppIndexed from WPF Element.

I am also attaching solution for reproducing,

scalingissuewpf.zip

This issue has been moved from https://developercommunity.visualstudio.com/content/problem/449544/wpf-font-scaling-problem-with-render-target-bitmap.html
VSTS ticketId: 789260
These are the original issue comments:
(no comments)
These are the original issue solutions:
(no solutions)

[ssalmanshah]

Hi Blair Wang,
What’s possible solution for this problem now?

Do I need to clone repository of Git and its fixed there?

Please let me know.
Waiting for response.

Thanks.

[mikedn]

All I want is to have homogeneous and smooth text rendering under different windows 10 scaling when rendering target bitmap @ Format1bppIndexed from WPF Element.

Smooth text rendering on a 1bpp bitmap is rather contradictory. 1bpp is black & white so you basically end up drawing up text without any kind of antialiasing.

[walterlv]

@vsfeedback It's recommended to use ![](imageurl) to post an image so that we can read your question directly without clicking into the linked images.

[rladuca]

@walterlv @vsfeedback is a bot that shuffles bugs from the VS Feedback site to GitHub. WPF doesn't own the code to it, but we'll bring up your suggestion to them. There might be specific reasons they don't want to embed images like that, perhaps to cut down traffic.

[ssalmanshah]

This is image difference when dragging canvas object

[Rand-Random]

Out of curiousity, why is here the correct place for this issue?
OP is stating that he is using .Net framework 4.6.1, so why would the GitHub page for WPF .Net Core 3.0, be the correct place?

[stevenbrix]

This is still a valid place to put all WPF related issues. The fact that it happens in .Net Framework 4.6.1 just means we might get to it after the initial release, since we're focusing on ensuring parity right now. Presumably this is still an issue in the netcore3 version of WPF, @ssalmanshah have you been able to confirm that?

[ssalmanshah]

Hi Steven, Thanks for the update. We are using .Net Framework 4 and yes this is happening in all WPF versions until now. In the attached project we can clearly see it.

…

On Thu, Apr 4, 2019 at 6:10 PM Steven Kirbach ***@***.***> wrote: This is still a valid place to put all WPF related issues. The fact that it happens in .Net Framework 4.6.1 just means we might get to it after the initial release, since we're focusing on ensuring parity right now. Presumably this is still an issue in the netcore3 version of WPF, @ssalmanshah <https://github.com/ssalmanshah> have you been able to confirm that? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#346 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AUFMpX_dA6D7BtaOwNeDbNT7XEOYgn_Qks5vdfnCgaJpZM4a1yPx> .

-- Syed Salman Sattar Shah. Microsoft Certified Professional PH # +92333-5204489

[mikedn]

It's still not clear how do you expect this to work. You are basically rendering text without antialiasing. It's simply not going to look smooth.

[ssalmanshah]

Basically its beyond Anti aliasing, if you try generate 1 format Bpp image while dragging it give you lag on every font.

…

On Fri, Apr 5, 2019 at 10:58 AM mikedn ***@***.***> wrote: It's still not clear how do you expect this to work. You are basically rendering text without antialiasing. It's simply not going to look smooth. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#346 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AUFMpcprlYpWLFFjn_ZUQer-Ow-iPoLNks5vduX4gaJpZM4a1yPx> .

-- Syed Salman Sattar Shah. Microsoft Certified Professional PH # +92333-5204489

[mikedn]

As far as I can tell the lag has nothing to do with 1bpp images and fonts, it's just the consequence of the way the image is updated - on a timer that fires every 200ms.

[ssalmanshah]

But Image should be smooth every time as this is doing with other image generation formats. And more to it stays in that partial rendered position even after multiple refreshes, so this is WPF conversion issue with Format 1 BPP.

…

On Fri, Apr 5, 2019 at 12:20 PM mikedn ***@***.***> wrote: As far as I can tell the lag has nothing to do with 1bpp images and fonts, it's just the consequence of the way the image is updated - on a timer that fires every 200ms. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#346 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AUFMpU_StXIz_-XheFyepS75BPQxfsQtks5vdvlSgaJpZM4a1yPx> .

-- Syed Salman Sattar Shah. Microsoft Certified Professional PH # +92333-5204489

[mikedn]

But Image should be smooth every time as this is doing with other image generation formats.

Hmm, can't seem to reproduce this. For me things are pretty smooth with a timer interval of 30ms. Changing the bitmap format doesn't seem to have any effect.

That said, the format conversion code that you're using is pretty convoluted and it involves System.Drawing. You could try to use FormattedConvertedBitmap instead of all that:

DiagramImage.Source = new FormatConvertedBitmap(targetBitmap, PixelFormats.BlackWhite, null, 0);

though it produces a different image and that may be a problem for you.

[ssalmanshah]

yes the image on the right is not workable for me as I only need black and white that can be done by removing background, but I need assurance that it did not have noise in dragging at different points.

…

On Fri, Apr 5, 2019 at 10:59 PM mikedn ***@***.***> wrote: But Image should be smooth every time as this is doing with other image generation formats. Hmm, can't seem to reproduce this. For me things are pretty smooth with a timer interval of 30ms. Changing the bitmap format doesn't seem to have any effect. That said, the format conversion code that you're using is pretty convoluted and it involves System.Drawing. You could try to use FormattedConvertedBitmap instead of all that: DiagramImage.Source = new FormatConvertedBitmap(targetBitmap, PixelFormats.BlackWhite, null, 0); though it produces a different image and that may be a problem for you. [image: image] <https://user-images.githubusercontent.com/9973420/55647185-b0fcde00-57e5-11e9-88ef-38d78258f0b0.png> — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#346 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AUFMpVkIp34NNu4B1VnABymRu6cxXr4fks5vd48NgaJpZM4a1yPx> .

-- Syed Salman Sattar Shah. Microsoft Certified Professional PH # +92333-5204489

[ssalmanshah]

Please see variation of middle image in this video

https://www.screencast.com/t/TmzJEdS6AZiR