LOGFONT text rotation increases the size of the font

Question

LOGFONT text rotation increases the size of the font

asad11 26

I tried rotating the text by 270 degrees but the size of the text also ends up changing.

HDC hdc = CreateCompatibleDC(NULL);
LOGFONT lf;

lf.lfHeight = 40;
lf.lfWidth = 0;
lf.lfEscapement = 2700;
lf.lfOrientation = 2700;
lf.lfWeight = FW_SEMIBOLD;
lf.lfItalic = 0;
lf.lfUnderline = 0;
lf.lfStrikeOut = 0;
lf.lfCharSet = DEFAULT_CHARSET;
lf.lfOutPrecision = 0;
lf.lfClipPrecision = 0;
lf.lfQuality = 0;
lf.lfPitchAndFamily = 0;
strcpy(lf.lfFaceName, "Arial");
hFont = CreateFontIndirect(&lf);

SelectObject(hdc, hFont);

TextOut(hdc, 120, 79, "hello", SIGNED_STRLEN("hello"));

However the size of the font gets bigger when the lfEscapement and lfOrientation parameters are set to 2700 for a 270 degrees as opposed to 0 for no rotation.

How do I keep the text size the same when I rotate it?
By size I mean lf.tmHeight or lf.tmWidth are -2 or -1 from when the text was not rotated.

Also what does the escapement have to do with the rotation? I couldn't understand from the documentation

David Lowndes 4,726 Reputation points

2022-05-20T16:21:12.207+00:00

If you don't specify the face name, does it make any difference?
Viorel 122.6K Reputation points

2022-05-20T18:40:08.173+00:00

Try specifying a negative size, for example: lf.lfHeight = -34.
asad11 26 Reputation points

2022-05-23T07:07:13.29+00:00

nope. Not specifying a name doesn't affect anything.
asad11 26 Reputation points

2022-05-23T07:07:28.253+00:00

that makes the text even bigger
Viorel 122.6K Reputation points

2022-05-23T07:15:07.65+00:00

Did you try other negative values (the same for rotated and non-rotated text) and check if the size on screen is different?
asad11 26 Reputation points

2022-05-23T07:23:49.24+00:00

Yes, so having a higher negative height will increase the font size for both rotated and non rotated text
Viorel 122.6K Reputation points

2022-05-23T07:56:28.037+00:00

According to original question, did you find a difference between the rotated and non-rotated text?
asad11 26 Reputation points

2022-05-23T08:15:36.367+00:00

So my question was why does rotation cause the font size to change. Of course I can reduce the height so that it just about matches what the text would look like without the rotation but the rotation itself shouldn't have been causing the font size change and it'll take extra work to adjust the height prior to the rotation.
Junjie Zhu - MSFT 21,646 Reputation points

2022-05-23T08:16:57.34+00:00

May I ask if my answer is helpful to you?
Viorel 122.6K Reputation points

2022-05-23T08:23:22.01+00:00

It is still not clear if the size appears different after rotation when you use a negative value in your experiments.
Junjie Zhu - MSFT 21,646 Reputation points

2022-05-24T06:39:39.677+00:00

Hi, is there any progress on this issue?
asad11 26 Reputation points

2022-05-24T10:56:08.343+00:00

Hi, I have read your response and understood what you have said. The thing is I was initially using 2 HDCs. I wrote the text into one of them, did the rotation and copied it into the other HDC using bitblt but this makes the text unselectable. As, from what I understand, the HDC that is being copied into doesn't know whether that copy is a picture or a piece of text.

Do you have another solution to this that doesn't involve copying in between buffers?
asad11 26 Reputation points

2022-05-24T10:57:40.583+00:00

No, I can definitely see the size increases with higher values irrespective of whether it was negative or positive after the rotation.
Castorix31 90,686 Reputation points

2022-05-24T11:45:52.707+00:00

I tested various flags in GDI (Antialiased and others) and I also don't get exactly the same size when rotated
But I tested in GDI+, and I get exactly the same font size (Rotate 90, not antialiased) :
Junjie Zhu - MSFT 21,646 Reputation points

2022-05-25T09:47:42.637+00:00

After reading Castorix31's comment, I also went and tested it with GDI+,
I use Graphics::RotateTransform to rotate the text. In GDI, the font attribute is used to achieve the rotation. In GDI+, many attributes are independent.
It does work, it seems that this is the best solution for you.
Junjie Zhu - MSFT 21,646 Reputation points

2022-05-30T05:47:48.687+00:00

It's been a few days, may I ask if our discussions and responses were helpful to your question?

Accepted answer

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Your answer

David Lowndes 4,726 Reputation points

2022-05-20T16:21:12.207+00:00

If you don't specify the face name, does it make any difference?
Viorel 122.6K Reputation points

2022-05-20T18:40:08.173+00:00

Try specifying a negative size, for example: lf.lfHeight = -34.
asad11 26 Reputation points

2022-05-23T07:07:13.29+00:00

nope. Not specifying a name doesn't affect anything.
asad11 26 Reputation points

2022-05-23T07:07:28.253+00:00

that makes the text even bigger
Viorel 122.6K Reputation points

2022-05-23T07:15:07.65+00:00

Did you try other negative values (the same for rotated and non-rotated text) and check if the size on screen is different?
asad11 26 Reputation points

2022-05-23T07:23:49.24+00:00

Yes, so having a higher negative height will increase the font size for both rotated and non rotated text
Viorel 122.6K Reputation points

2022-05-23T07:56:28.037+00:00

According to original question, did you find a difference between the rotated and non-rotated text?
asad11 26 Reputation points

2022-05-23T08:15:36.367+00:00

So my question was why does rotation cause the font size to change. Of course I can reduce the height so that it just about matches what the text would look like without the rotation but the rotation itself shouldn't have been causing the font size change and it'll take extra work to adjust the height prior to the rotation.
Junjie Zhu - MSFT 21,646 Reputation points

2022-05-23T08:16:57.34+00:00

May I ask if my answer is helpful to you?
Viorel 122.6K Reputation points

2022-05-23T08:23:22.01+00:00

It is still not clear if the size appears different after rotation when you use a negative value in your experiments.
Junjie Zhu - MSFT 21,646 Reputation points

2022-05-24T06:39:39.677+00:00

Hi, is there any progress on this issue?
asad11 26 Reputation points

2022-05-24T10:56:08.343+00:00

Hi, I have read your response and understood what you have said. The thing is I was initially using 2 HDCs. I wrote the text into one of them, did the rotation and copied it into the other HDC using bitblt but this makes the text unselectable. As, from what I understand, the HDC that is being copied into doesn't know whether that copy is a picture or a piece of text.

Do you have another solution to this that doesn't involve copying in between buffers?
asad11 26 Reputation points

2022-05-24T10:57:40.583+00:00

No, I can definitely see the size increases with higher values irrespective of whether it was negative or positive after the rotation.
Castorix31 90,686 Reputation points

2022-05-24T11:45:52.707+00:00

I tested various flags in GDI (Antialiased and others) and I also don't get exactly the same size when rotated
But I tested in GDI+, and I get exactly the same font size (Rotate 90, not antialiased) :
Junjie Zhu - MSFT 21,646 Reputation points

2022-05-25T09:47:42.637+00:00

After reading Castorix31's comment, I also went and tested it with GDI+,
I use Graphics::RotateTransform to rotate the text. In GDI, the font attribute is used to achieve the rotation. In GDI+, many attributes are independent.
It does work, it seems that this is the best solution for you.
Junjie Zhu - MSFT 21,646 Reputation points

2022-05-30T05:47:48.687+00:00

It's been a few days, may I ask if our discussions and responses were helpful to your question?

Answer 1

Hello,
Welcome to Microsoft Q&A!

1. Background

ClearType, a software technology developed by Microsoft that improves the readability of text on existing LCDs (Liquid Crystal Displays), In ClearType font rendering, the width of 'm' becomes smaller after rendering.

2. Why does the text become different after rotation?

When GDI displays strings horizontally, each subsequent character starts at the decimal place, which is simulated by antialiasing or subpixel (ClearType) display. However, when rendered vertically, the starting position of each subsequent character is rounded to the next whole pixel, which tends to make vertical text a few pixels "longer" than horizontal text.

3. How to solve this issue?

lf.lfQuality = ANTIALIASED_QUALITY;

Use ANTIALIASED_QUALITY, Make sure the rendered pixels are the same.
For vertical text content, draw them horizontally to an offscreen buffer, rotate it, and set the buffer to the screen. This makes vertical text and horizontal text look exactly the same.

**4. Solution from @Castorix31 **
You can use GDI+ to draw text and use Graphics::RotateTransform to rotate text.

Thank you.

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LOGFONT text rotation increases the size of the font

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