VFont: Corrections to Cursor When on Curve #107307

Harley Acheson · 2023-04-24T19:13:11+02:00

Harley Acheson commented

2023-04-24 19:13:11 +02:00

Corrections to transformation and placement of the text cursor when the
text is being deformed by a curve.

When a text object is deformed by a curve the text cursor (caret) needs to be shown at an angle. Unfortunately this transformation isn't done correctly so the top and bottom edges are not aligned correctly and it become non-rectangular. And the angle quite often does not look quite right:

The PR just transforms the cursor correctly so that it remains rectangular after rotation. And it chooses the rotation better, matching nicer on first and last character and to the beginning or end of a selection. Overall it just looks a bit better:

This PR is offered as a much simpler alternative to #107193.

Corrections to transformation and placement of the text cursor when the text is being deformed by a curve. ---- When a text object is deformed by a curve the text cursor (caret) needs to be shown at an angle. Unfortunately this transformation isn't done correctly so the top and bottom edges are not aligned correctly and it become non-rectangular. And the angle quite often does not look quite right: ![CursorCurve.png](/attachments/d626f428-7643-47c6-9646-c2cee8ae9e9e) The PR just transforms the cursor correctly so that it remains rectangular after rotation. And it chooses the rotation better, matching nicer on first and last character and to the beginning or end of a selection. Overall it just looks a bit better: ![TextSelectCurve.gif](/attachments/f780743d-e8f7-474c-8a5d-66141940edf9) This PR is offered as a much simpler alternative to #107193.

TextSelectCurve.gif

186 KiB

CursorCurve.png

52 KiB

🚀 1

Harley Acheson added this to the User Interface project 2023-04-24 19:25:59 +02:00

Harley Acheson requested review from Campbell Barton 2023-04-25 17:46:08 +02:00

Campbell Barton requested changes 2023-04-26 03:12:47 +02:00

source/blender/blenkernel/intern/vfont.c Outdated

						
				@ -1546,3 +1540,1 @@

				    f[0] = font_size * (-0.02f * co + ct->xof);

				    f[1] = font_size * (0.1f * si - (0.25f * co) + ct->yof);

				    float width = 0.02f;

Campbell Barton commented

2023-04-26 03:11:42 +02:00

These can be made const.

These can be made `const`.

Harley marked this conversation as resolved

source/blender/blenkernel/intern/vfont.c Outdated

						
				@ -1549,0 +1542,4 @@

				    float left = ct->xof;

				    float bottom = ct->yof;

				    float rotation = ct->rot;

				    float caret_nudge = 0.0f;

Campbell Barton commented

2023-04-26 03:10:09 +02:00

Use term cursor instead of caret.

There should be an explanation why the nudge is needed, it also seems only to apply to the X axis, so cursor_offset_x with a description for why the small amount of X offset is needed (what does it solve?).

Use term `cursor` instead of `caret`. There should be an explanation why the nudge is needed, it also seems only to apply to the X axis, so `cursor_offset_x` with a description for why the small amount of X offset is needed (what does it solve?).

Harley marked this conversation as resolved

source/blender/blenkernel/intern/vfont.c Outdated

						
				@ -1558,0 +1577,4 @@

				      float temp_fl[2];

				      rotate_v2_v2fl(temp_fl, &ef->textcurs[i][0], -rotation);

				      ef->textcurs[i][0] = font_size * (left + temp_fl[0]);

				      ef->textcurs[i][1] = font_size * (bottom + temp_fl[1] - 0.25f);

Campbell Barton commented

2023-04-26 03:11:23 +02:00

What does 0.25 represent? Applying an offset after rotation seems strange.

May as well assign to a const float with a descriptive name.

What does `0.25` represent? Applying an offset after rotation seems strange. May as well assign to a `const` float with a descriptive name.

Harley marked this conversation as resolved

Harley Acheson commented

2023-04-26 23:45:06 +02:00

@ideasman42 - I think I have made it easier to follow, including any need for that "nudge"

a description for why the small amount of X offset is needed (what does it solve?).

I put in detailed comments, but there are times when the cursor should align with the character to the right and sometimes to the left, like when there is a selection. if the cursor is at the left edge of a selection is is nice to move it to the edge of the selection rather than straddling it to show more of the selected text.

What does 0.25 represent? Applying an offset after rotation seems strange.

I am hoping my comments explain that enough. Basically when on a curve the characters are rotated by their bottom left corner. So the cursor's bottom-left corner is similarly in the correct position. If we apply offsets before rotation the cursor moves incorrectly because rotate_v2_v2fl rotates around {0,0), so here I am moving the cursor so that the rotation origin is where I want it, rotate, then apply offsets. I think it would be clearer if we had a version of rotate_v2_v2fl that could rotate around a different origin than just {0,0}.

Without that "0.25" downward movement the cursor would have its bottom point on the baseline, but we want it 75% above and 25% below so lines up better with most fonts that have descenders.

@ideasman42 - I think I have made it easier to follow, including any need for that "nudge" > a description for why the small amount of X offset is needed (what does it solve?). I put in detailed comments, but there are times when the cursor should align with the character to the right and sometimes to the left, like when there is a selection. if the cursor is at the left edge of a selection is is nice to move it to the edge of the selection rather than straddling it to show more of the selected text. > What does 0.25 represent? Applying an offset after rotation seems strange. I am hoping my comments explain that enough. Basically when on a curve the characters are rotated by their bottom left corner. So the cursor's bottom-left corner is similarly in the correct position. If we apply offsets before rotation the cursor moves incorrectly because `rotate_v2_v2fl` rotates around {0,0), so here I am moving the cursor so that the rotation origin is where I want it, rotate, then apply offsets. I think it would be clearer if we had a version of `rotate_v2_v2fl` that could rotate around a different origin than just {0,0}. Without that "0.25" downward movement the cursor would have its bottom point on the baseline, but we want it 75% above and 25% below so lines up better with most fonts that have descenders.

Campbell Barton approved these changes 2023-04-27 02:35:27 +02:00

Harley Acheson commented

2023-04-27 19:22:39 +02:00

@blender-bot build

Harley Acheson force-pushed CurveCursor from 28ea3e0af1 to ac92a4a9bf

2023-04-27 20:25:19 +02:00

Compare

Harley Acheson commented

2023-04-27 20:26:04 +02:00

@blender-bot build

Harley Acheson added 1 commit 2023-04-27 21:36:34 +02:00