Getting line height in Cinder-SDFText

1

I’m using Cinder-SDFText (my fork here and have been running into issues with measuring line height. I’m currently drawing several sample strings of text using the following code in my draw loop:

for (auto& string : mSampleText) {
        gl::color(0.45f, 0.45f, 0.45f);
        gl::drawLine(vec2(0, baseline.y), vec2(getWindowWidth(), baseline.y));

        gl::color(0, 1, 0);
        if (mDrawBoundingBoxes) {
            ci::gl::pushMatrices();
            ci::gl::translate(baseline);
            gl::drawStrokedRect(currentFont->measureStringBounds(string));
            ci::gl::popMatrices();
        }

        gl::color(1, 1, 1);
        currentFont->drawString(string, baseline);

        baseline.y += currentFont->getHeight();

By default in my application I’m using size 38 font, and everything seems to look right:

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However, if I change my font size to 89, gl::SdfTextRef::getHeight() doesn’t seem to give the correct value:

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In fact, gl::SdfText::Font::getHeight() gives me the same value as well. If I rebuild the gl::SdfText object for different font sizes, I still get the same font values:

|info   | TypographyAnatomyApp::update[102] Font Size: 38
|info   | TypographyAnatomyApp::update[103] Font Height: 36.7969
|info   | TypographyAnatomyApp::update[104] Font Leading: 1.04688
|info   | TypographyAnatomyApp::update[105] Font Ascent: 28.9688
|info   | TypographyAnatomyApp::update[106] Font Descent: 6.78125
|info   | TypographyAnatomyApp::update[102] Font Size: 89
|info   | TypographyAnatomyApp::update[103] Font Height: 36.7969
|info   | TypographyAnatomyApp::update[104] Font Leading: 1.04688
|info   | TypographyAnatomyApp::update[105] Font Ascent: 28.9688
|info   | TypographyAnatomyApp::update[106] Font Descent: 6.78125

These numbers change on a per-Font basis, so these seem to be properties related to the font’s inherent design rather than the specific size I’m rendering at. Comments in SdfText.cpp seem to suggest that the base scale for the sdf texture generation is size 32, so these could all be reference sizes for the texture file that’s being generated internally.

It seems like measureStringImpl is able to get the proper sizes for the current font size; if I use gl::SdfText::measureStringBounds() to draw the bounding rectangle, I get the right size:

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but obviously this is the bounding size of the specific string I drew (with descender, ascenders, etc.) and doesn’t give me the line height.

I’m currently trying to figure out how to extract this information from the block; ideally I could update these getters in SdfText or SdfText::Font to give me the specifics for the current font, but I don’t have a high-enough level view of how this block was designed to know what should live where in a way that won’t just make a mess out of everything.

Is anyone familiar enough with how Cinder-SDFText works to help me figure this out?

If anyone wants to investigate further, the app I’m testing with is included here