RichTextLabel
lags on first draw
RichTextLabel
uses TextParagraph internally to draw
text, but since TextParagraph caches
some information lazily there can be a lag spike
when drawing the RichTextLabel for the
first time.
To get around this issue, you can disable the use
of system fonts as a fallback or use the
TextParagraph class directly, and force
it to cache the information it needs before the
first draw call:
@tool
class_name CachedTextLabel
extends Control
@export_multiline var text: String:
set(value):
if text != value:
text = value
var font := get_theme_default_font()
var font_size := get_theme_default_font_size()
paragraph = TextParagraph.new()
paragraph.add_string(text, font, font_size)
queue_redraw()
var paragraph: TextParagraph
func _ready() -> void:
# Force the paragraph to cache some data before the first draw
paragraph.get_size()
func _draw() -> void:
var start := Time.get_ticks_msec()
paragraph.width = size.x
paragraph.break_flags = TextServer.BREAK_MANDATORY | TextServer.BREAK_WORD_BOUND
paragraph.justification_flags = TextServer.JUSTIFICATION_NONE
paragraph.alignment = HORIZONTAL_ALIGNMENT_LEFT
paragraph.draw(get_canvas_item(), Vector2.ZERO)
var end := Time.get_ticks_msec()
print("_draw: ", end - start, "ms")Unfortunately, TextParagraph does
not support BBCode.