Make glyph with multiple contours bolder bug

[Hafonton]

Problem:
Sometimes when I make a glyph that has overlapping contours and I try to make them bolder,
it changes the direction of some contours, therefore, making some contours lighter, and the others bolder.

Suggested solution:
prevent changing the direction of the contours when performing a bold/thin effect.

Example:


How to reproduce:
1. download the attached font
2. select the glyph and bold it (20 horizontal 20 vertical)

[Bhikkhu Pesala]

The bug is in your font. These contours should be joined with Get Union of Contours before applying any bold transformation.

That being said, bold and thin transformations will often introduce errors like intersecting contours. A lot of these could be avoided by implement the long-standing feature request for bold and thin transforms to use relatives values instead of absolute values.

[Hafonton]

These contours should be joined with Get Union of Contours before applying any bold transformation.

I see that, but I want to keep the contours separate (because I still work on the font).
To my eyes, the contours should remain their direction (clockwise or counter clockwise) when a thin/bold function is done.

That being said, bold and thin transformations will often introduce errors like intersecting contours. A lot of these could be avoided by implement the long-standing feature request for bold and thin transforms to use relatives values instead of absolute values.

That's a nice feature request indeed, though I don't really think it relates to the problem I'm facing.

[Bhikkhu Pesala]

That's a nice feature request indeed, though I don't really think it relates to the problem I'm facing.

It is the same issue. The transform scripts move nodes by the defined number of funits, which can make them cross over themselves.

[Hafonton]

It is the same issue. The transform scripts move nodes by the defined number of funits, which can make them cross over themselves.

What is funits?

[Bhikkhu Pesala]

The font units (funits) or units per em are set on the General Tab of the Font Properties dialog. They are the units used on the rulers in the Glyph Edit Window.

The default is 2048 units/em but Apple fonts typically use 1000 units/em. Using the cursor keys moves a node by 10 funits, holding Ctrl limits the movement to 1 funit, while holding the Shift key increases the movement to 100 funits per keystroke. If I remember rightly, the glyph transform scripts assume 2048 funits per em, and adjust the movement automatically for other values.

Font Units Per Em.png (17.98 KiB) Viewed 1756 times

Computers like powers of 2. If your fonts have fine detail, increase the default to 4096 or 8192 so that tiny circles are circles and not squircles.

Here is an animation of the bold transformation on my Mandala font, which illustrates the problem of nodes crossing over contours.

Bold Transformation.png (19.78 KiB) Viewed 1756 times

[Hafonton]

Cool, thanks for explaining.
What is the expected result you want by making your letter bolder? Can you show?

[Bhikkhu Pesala]

If the transformation was proportional, not absolute, thick strokes would get much thicker, but narrow strokes would not change nearly as much. The Baseline, Cap Height, and x-height would not change at all.

Acariya Bold Transform.png (30.76 KiB) Viewed 1751 times

In case of fonts like Mandala, where the stroke weights are even, that is not an issue, but perhaps the overlapping could be avoided somehow. It is a difficult puzzle to solve. I have had previous discussions with Erwin about this.

Mandala Regular.png (15.52 KiB) Viewed 1751 times

Mandala Bold.png (15.71 KiB) Viewed 1751 times

[Hafonton]

I see.
That's a wonderful idea for a feature request!
Making a proportional bold/light effect is a very useful and I would like it as well, if its possible.
But I think it deserves its own thread.

To my understanding, my problem is different then yours.
The problem I'm facing is different and much a simpler problem to solve.
As you can see, when I make a font bold (that has overlapping contours), while all the contours are clockwise (which is good), when I perform thin/bold effect some of them turn counter-clockwise, therefore, making some contours thin instead of bold.
On the right glyph (green marked) I "solved" it by merging the contours as you said before performing the bold effect. But that's exactly the problem - I want to keep the contours seperate, I don't want to merge them.
On the left glyph (red marked) you can see that the contours are not merged (And I want to keep that way).

Again, I don't mind that its 'crossing' over the baseline and the proportion changes. That's actually a good thing in my case (it helps me shape the letter exactly the way I want).
That's why its a different problem than what you're saying.
Though, I'd love to support your feature request.

[Bhikkhu Pesala]

1. Cut the vertical stem to the clipboard
2. Run the bold transformation
3. Paste the vertical stem from the clipboard
4. Cut the horizontal strokes to the clipboard
5. Run the bold transformation again
6. Paste the horizontal strokes from the clipboard

As I said at the start; this is not a bug in FontCreator. The problem lies in the overlapping contours.

I wonder if it is even possible for software to deal with unexpected situations like this. Garbage in, garbage out, is what one would expect. I notice that Erwin has not responded to the thread. Only he can know what is feasible.

[Erwin Denissen]

I wonder if it is even possible for software to deal with unexpected situations like this. Garbage in, garbage out, is what one would expect. I notice that Erwin has not responded to the thread. Only he can know what is feasible.

I think you've covered it all. I'm sure we can further improve the software, but what you explained is what can be done right now.

[Hafonton]

1. Cut the vertical stem to the clipboard
2. Run the bold transformation
3. Paste the vertical stem from the clipboard
4. Cut the horizontal strokes to the clipboard
5. Run the bold transformation again
6. Paste the horizontal strokes from the clipboard

As I said at the start; this is not a bug in FontCreator. The problem lies in the overlapping contours.

I wonder if it is even possible for software to deal with unexpected situations like this. Garbage in, garbage out, is what one would expect. I notice that Erwin has not responded to the thread. Only he can know what is feasible.

Thanks for sharing, I know this trick, I think I learned it from someone in the forum (probably you).
I understand. Let's see what Erwin has to say, hoping both our problems can be solved.

[Hafonton]

I wonder if it is even possible for software to deal with unexpected situations like this. Garbage in, garbage out, is what one would expect. I notice that Erwin has not responded to the thread. Only he can know what is feasible.

I think you've covered it all. I'm sure we can further improve the software, but what you explained is what can be done right now.

Okay. Thanks for taking the time to read this