Create problems_with_variable_fonts/content.md

cc-by-sa/knowledge/modules/using_variable_fonts_on_the_web/lessons/factors_that_influence_the_efficiency_of_variable_web_fonts/lesson.textproto

@@ -5,4 +5,5 @@ reviewers: "Piper Haywood"
 topics: "variable_fonts"
 related_terms: "variable_fonts"
 prev_lessons: "interactive_animations_with_variable_fonts"
+next_lessons: "problems_with_variable_fonts"
 excerpt: "Which specific font qualities make the biggest impact on efficiency?"

cc-by-sa/knowledge/modules/using_variable_fonts_on_the_web/lessons/problems_with_variable_fonts/content.md

@@ -0,0 +1,48 @@
+## Variable fonts are not supported at all
+
+Variable font was introduced to the web in 2016, but some applications still do not offer any support for them.
+
+To help with this situation, Google Fonts offers download ZIPs for each variable font family that include a set of commonly used static fonts.
+But it is common that you will want to use a specific style that was not included.
+
+There are several tools available to convert such an 'instance' into a static font, that will work everywhere:
+
+* [Dinamo Font Gauntlet](https://fontgauntlet.com) 
+* [Slice](https://slice-gui.netlify.app)
+
+## Glyph outline overlaps causing holes
+
+When variable fonts are supported, the most common technical problem encountered is with glyph outline contours that overlap.
+When it occurs, the problem looks something like this:
+
+<figure>
+
+![A 3D graphics editor screenshot, showing variable font glyphs B, P, R, e, and 4 with contour overlaps that are not correctly processed.](images/1.png)
+
+<figcaption>A variable font with glyphs B, P, R, e, and 4 that have contour overlaps, rendered in a 3D graphics editor incorrectly with holes.</figcaption>
+
+</figure>
+
+Here the glyphs in a 3D animation tool have contour overlaps, but they are rendered incorrectly, causing unwanted holes in the letterforms.
+
+Sadly, this is not a problem with the font, but with the application. 
+These overlaps are intrinsic to how variable fonts vary, and can not be removed from the font itself.
+Many apps only offer the most basic support for variable fonts, and are not fully tested across all of their features by the developer.
+
+This situation began in the early 1980s, when Adobe released its first font format.
+At that time, Adobe specified that glyph outlines should not have contour overlaps. 
+Over time, many apps have been built with an assumption that such overlaps do not occur. 
+These apps offers text styling features, which add shadow, strokes, fills, and other treatments to text by processing the glyph outlines.
+But when the overlaps are present, these processes give really weird output.
+
+Fortunately, in all these apps, the workaround is always the same: 
+
+**Apply a "Boolean union" function to remove the overlaps.** 
+
+A Google search for ["boolean shape union APPNAME"](https://www.google.com/search?q=boolean+shape+union) should pull up the specifics for any app. 
+
+A first preparatory step may also be needed, to ["convert text to outlines"](https://www.google.com/search?q=%22convert+text+to+outlines%22).
+
+Applying a union operation often means turning "live text" into a "dead graphic", so that the text with a font choice to render the text with the font's glyphs, is converted to a set of graphic objects; the original text is lost, so editing the text requires recreating the graphic objects. 
+
+3D and motion apps tends to have "node" or "pipeline" structured editing environments, where the union operation can be applied to live text as part of a multi-step process that also sets the extrusion depth, shadow, and other treatments of the text.

cc-by-sa/knowledge/modules/using_variable_fonts_on_the_web/lessons/problems_with_variable_fonts/lesson.textproto

@@ -0,0 +1,8 @@
+name: "Problems with variable fonts"
+authors: "Dave Crossland"
+reviewers: "Laurence Penney"
+reviewers: "Elliot Jay Stocks"
+topics: "variable_fonts"
+related_terms: "variable_fonts"
+prev_lessons: "factors_that_influence_the_efficiency_of_variable_web_fonts"
+excerpt: "Variable fonts are still a relatively new technology, and users encounter common technical problems using them, that often have workarounds."