OpenSCAD User Manual/Text

text() The text module creates text as a 2D geometric object, using fonts installed on the local system or provided as separate font file. 2015.03 Parameters text String. The text to generate. size Number. In a western script, capital letters will be approximately this tall. Default is 10. Sets the em size of the font to 100/72 times the value specified. See em and the note on font sizes below. font String. The name of the font that should be used. This is not the name of the font file, but the logical font name (internally handled by the fontconfig library). This can also include a style parameter, see below. A list of installed fonts & styles can be obtained using the font list dialog (in the Help or Windows menu, depending on version). The default is "Liberation Sans". direction String. Direction of the text flow. Possible values are "ltr" (left-to-right), "rtl" (right-to-left), "ttb" (top-to-bottom) and "btt" (bottom-to-top). Default is "ltr". language String. The language of the text (e.g., "en", "ar", "ch"). Default is "en". script String. The script of the text (e.g., "latin", "arabic", "hani"). Default is "latin". halign String. The horizontal alignment for the text. Possible values are "left", "center" and "right". Default is "left". valign String. The vertical alignment for the text. Possible values are "top", "center", "baseline" and "bottom". Default is "baseline". spacing Number. Factor to increase/decrease the character spacing. The default value of 1 results in the normal spacing for the font, giving a value greater than 1 causes the letters to be spaced further apart. em Number. Specifies the size of an em-square. This is the conventional measurement used for font sizing; see the note on font sizing below. Development snapshot $fn, $fs, and $fa used for subdividing curved segments of the glyphs. Example thumb|Example 1: Result. text("OpenSCAD"); Alignment Vertical alignment top The text is aligned so the top of the tallest character in your text is at the given Y coordinate. center The text is aligned with the center of the bounding box at the given Y coordinate. This bounding box is based on the actual sizes of the letters, so taller letters and descenders will affect the positioning. baseline The text is aligned with the font baseline at the given Y coordinate. This is the default, and is the only option that makes different pieces of text align vertically, as if they were written on lined paper, regardless of character heights and descenders. bottom The text is aligned so the bottom of the lowest-reaching character in your text is at the given Y coordinate. thumb|OpenSCAD vertical text alignment text = "Align"; font = "Liberation Sans"; valign = [ [ 0, "top"], [ 40, "center"], [ 75, "baseline"], [110, "bottom"] ]; for (a = valign) { translate([10, 120 - a[0], 0]) { color("red") cube([135, 1, 0.1]); color("blue") cube([1, 20, 0.1]); linear_extrude(height = 0.5) { text(text = str(text,"_",a[1]), font = font, size = 20, valign = a[1]); } } } The text() module doesn't support multi-line text, but you can make a separate call for each line, using translate() to space them. A spacing of 1.4*size is the minimum required to prevent lines overlapping (if they include descenders). 1.6*size is approximately the default single-spacing in many word processing programs. To get evenly spaced lines, use "baseline" vertical alignment; otherwise, lines may be lower or higher depending on their contents. Horizontal alignment left The text is aligned with the left side of the bounding box at the given X coordinate. This is the default. center The text is aligned with the center of the bounding box at the given X coordinate. right The text is aligned with the right of the bounding box at the given X coordinate. thumb|OpenSCAD horizontal text alignment text = "Align"; font = "Liberation Sans"; halign = [ [10, "left"], [50, "center"], [90, "right"] ]; for (a = halign) { translate([140, a[0], 0]) { color("red") cube([115, 2,0.1]); color("blue") cube([2, 20,0.1]); linear_extrude(height = 0.5) { text(text = str(text,"_",a[1]), font = font, size = 20, halign = a[1]); } } } Using Fonts & Styles Fonts are specified by their logical font name; in addition a style parameter can be added to select a specific font style like "bold" or "italic", such as: font="Liberation Sans:style=Bold Italic" The font list dialog (in the Help or Windows menu, depending on version) shows the font name and the font style for each available font. For reference, the dialog also displays the location of the font file. You can drag a font in the font list into the editor window to use in the text() statement. thumb|center|400px|OpenSCAD font list dialog OpenSCAD includes the fonts Liberation Mono, Liberation Sans, and Liberation Serif. Hence, as fonts in general differ by platform type, use of these included fonts is likely to be portable across platforms. For common/casual text usage, the specification of one of these fonts is recommended for this reason. Liberation Sans is the default font to encourage this. In addition to the installed fonts ( for windows only fonts installed as admin for all users ), it's possible to add project specific font files. Supported font file formats are TrueType Fonts (*.ttf) and OpenType Fonts (*.otf). The files need to be registered with use<>. use <ttf/paratype-serif/PTF55F.ttf> After the registration, the font is listed in the font list dialog, so in case logical name of a font is unknown, it can be looked up as it was registered. Example thumb|Example 2: Result. square(10); translate([15, 15]) { text("OpenSCAD", font = "Liberation Sans"); } translate([15, 0]) { text("OpenSCAD", font = "Liberation Sans:style=Bold Italic"); } Metrics Development snapshot textmetrics() The textmetrics() function accepts the same parameters as text(), and returns an object describing how the text would be rendered. The returned object has these members: position: the position of the lower-left corner of the generated text. size: the size of the generated text. ascent: the amount that the text extends above the baseline. descent: the amount that the text extends below the baseline. offset: the origin of the text after aligning. Text typically starts slightly right of this point. advance: the "other end" of the text, the point at which additional text should be positioned, relative to "offset". Text generally ends slightly left of this point. s = "Hello, World!"; size = 20; font = "Liberation Serif"; tm = textmetrics(s, size=size, font=font); echo(tm); translate([0,0,1]) text("Hello, World!", size=size, font=font); color("black") translate(tm.position) square(tm.size); yields (reformatted for readability): thumb|Using textmetrics() to draw a box around text ECHO: { position = [0.7936, -4.2752]; size = [149.306, 23.552]; ascent = 19.2768; descent = -4.2752; offset = [0, 0]; advance = [153.09, 0]; } fontmetrics() The fontmetrics() function accepts a font size and a font name, both optional, and returns an object describing global characteristics of the font. Parameters size Number, optional. The approximate height of capital letters, as described above for text(). font String, optional. The name of the font, as described above. em Number, optional. The font size, the size of the em-square, as described above. Note that omitting the size and/or font may be useful to get information about the default font. Returns an object: nominal: usual dimensions for a glyph: ascent: height above the baseline descent: depth below the baseline max: maximum dimensions for a glyph: ascent: height above the baseline descent: depth below the baseline interline: design distance from one baseline to the next font: identification information about the font: family: the font family name style: the style (Regular, Italic, et cetera) echo(fontmetrics(font="Liberation Serif")); yields (reformatted for readability): ECHO: { nominal = { ascent = 12.3766; descent = -3.0043; }; max = { ascent = 13.6312; descent = -4.2114; }; interline = 15.9709; font = { family = "Liberation Serif"; style = "Regular"; }; } Notes Font sizing Parameters: size and em size sets the size of the text in a convenient way: it sets, approximately, the height of a capital letter in a western script. em sets the size of the text in the industry-standard way: it sets the size of the em-square. If you try to precisely correlate either of these measurements to any particular dimension of the generated text, you are likely to be unsatisfied. size is based on a miscalculation that is now maintained for compatibility. By accident, the result is that size approximately sets the size of capital letters. Fonts vary and may be a different height, typically slightly smaller. em is the conventional way to specify font size. Its behavior - its relationship with other measurements - matches the behavior seen in other applications and typography conventions. However, because historically it specified the size of the block of metal used to print the text, it's considerably larger than most letters. The exact relationship between the nominal font size and the actual size of glyphs depends on the design of the font. For most western fonts, the height of capital letters is about 70% of the font size. textmetrics() can be used to measure the dimensions of any particular text; fontmetrics() will return general information about the font. You can use those results to scale when you need the actual text to be a particular size. Units: points, millimeters, or...? A common point of confusion is in the units used to specify font sizes. Conventional usage specifies font sizes in points, at 72 points per inch. This yields convenient numbers like 10 for typical text sizes, but there is nothing special about points; those sizes could equally be specified in inches, millimeters, or miles. OpenSCAD has no units. There may be units specified in exported file formats, or inferred by downstream tools, but OpenSCAD proper does not define how large a 10-unit cube is in physical units. Similarly, the size of text in OpenSCAD is specified in OpenSCAD units - which might be interpreted as millimeters or feet. If you use em to specify a font size of 10, you will typically get text where, as noted above, capital letters are about 7 units tall. It is common for users to interpret OpenSCAD units as millimeters. When interpreting OpenSCAD units as millimeters, if you want to specify text sizes in points you'll want to multiply the desired size in points by 25.4/72 to get the equivalent size in millimeters. 3D text thumb|3D text example Text can be changed from a 2 dimensional object into a 3D object by using linear_extrude. //3d Text Example linear_extrude(4) text("Text"); Unicode To allow specification of particular Unicode characters, you can specify them in a string with the following escape codes; \x03     - hex char-value (only hex values from 01 to 7f are supported) \u0123   - Unicode char with 4 hexadecimal digits (note: lowercase \u) \U012345 - Unicode char with 6 hexadecimal digits (note: uppercase \U) The null character (NUL) is mapped to the space character (SP). assert(version() == [2019, 5, 0]); assert(ord(" ") == 32); assert(ord("\x00") == 32); assert(ord("\u0000") == 32); assert(ord("\U000000") == 32); Example t="\u20AC10 \u263A"; // 10 euro and a smiley Font management OpenSCAD uses fontconfig to find and manage fonts, so it's possible to list the system configured fonts on command line using the fontconfig tools in a format similar to the GUI dialog. $ fc-list -f "%-60{{%{family[0]}%{:style[0]=}}}%{file}\n" | sort ... Liberation Mono:style=Bold Italic /usr/share/fonts/truetype/liberation2/LiberationMono-BoldItalic.ttf Liberation Mono:style=Bold /usr/share/fonts/truetype/liberation2/LiberationMono-Bold.ttf Liberation Mono:style=Italic /usr/share/fonts/truetype/liberation2/LiberationMono-Italic.ttf Liberation Mono:style=Regular /usr/share/fonts/truetype/liberation2/LiberationMono-Regular.ttf ... Under Windows, fonts are stored in the Windows Registry. To get a file with the font file names, use the command: reg query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts" /s > List_Fonts_Windows.txt