Text rendering is the process of displaying text on the stage, usually in ways more flexible than the use of the say block or stage monitors.
There are many ways this can be achieved, including:
- Using a set of sprite costumes to display images of letters, either cloned or stamped.
- Using pen lines to draw letters.
- Using pen dots to make a bitmap image or dot matrix.
A "string" is a piece of text, composed of a sequence of "characters" (letters, numbers, and/or symbols).
Stamped Costume Method
The examples in this section use the Stamp block. It is possible to achieve the same visual effect by creating clones: Simply replace each Stamp block with a Create Clone of (myself) block. However, the use of clones has two disadvantages:
- Creating and managing clones is prone to lag.
- A maximum of 300 clones can be displayed simultaneously.
Setup
Firstly, obtain or create costumes for each character. Each costume should be named the character it represents. Costume names are case sensitive so you can have a distinct character for "A" and "a", for example. If rendering spaces between words is needed, don't forget to also create an empty costume named with a space.
Script
define render text (text) at x: (text x) y: (text y) go to x: (text x) y: (text y) // move to text start position set [i v] to [1] // counter repeat (length of (text)) // loop over the characters in the string switch costume to (letter (i) of (text)) stamp // leave an image of this letter change x by (10) // move to next letter position change [i v] by (1) // increment counter to go to the next character end
 Note: | Set the custom block to "run without screen refresh" to draw all the text instantly. |
The script assumes all the characters have the same width. If not, see "Varying Letter Widths" below.
Varying Character Widths
This section builds on the tutorials above.
To accomplish this, create a list to store the widths: (character widths::list). For each costume, enter its width measurement into the list. Add 1 or 2px to the number so the characters can have small gaps between each other. Make sure that the costume number corresponds with the list number!
In the text rendering script, replace:
change x by (10)
With:
change x by (item (costume [number v]) of [character widths v])
To test that all of the letter widths are correct, it can be helpful to print out every letter and character supported as well as some sentences.
Symbols
Text sprites aren't limited to letters, numbers and a few special characters. Text sprites might also have symbols.
Pen Drawing Method
This is a complicated method requiring the shape of each character to be stored in a list as a series of strokes. Case sensing is often handled with costumes so there is some similarity with the stamped method above.
