RichTextLabel 中的 BBCode

前言

Label nodes are great for displaying basic text, but they have limitations. If you want to change the color of the text, or its alignment, you can only do that to the entire label. You can’t make a part of the text have another color, or have a part of the text centered. To get around these limitations, you would use a RichTextLabel.

RichTextLabel allows for complex formatting of text using a markup syntax or the built-in API. It uses BBCodes for the markup syntax, a system of tags that designate formatting rules for a part of the text. You may be familiar with them if you ever used forums (also known as bulletin boards, hence the “BB” in “BBCode”).

Unlike Label, RichTextLabel also comes with its own vertical scrollbar. This scrollbar is automatically displayed if the text does not fit within the control’s size. The scrollbar can be disabled by unchecking the Scroll Active property in the RichTextLabel inspector.

Note that the BBCode tags can also be used to some extent in the XML source of the class reference. For more information, see 类参考入门.

参见

You can see how BBCode in RichTextLabel works in action using the Rich Text Label with BBCode demo project.

使用 BBCode

By default, RichTextLabel functions like a normal Label. It has the property_text property, which you can edit to have uniformly formatted text. To be able to use BBCode for rich text formatting, you need to turn on the BBCode mode by setting bbcode_enabled. After that, you can edit the text property using available tags. Both properties are located at the top of the inspector after selecting a RichTextLabel node.

For example, BBCode [color=green]test[/color] would render the word “test” with a green color.

Most BBCodes consist of 3 parts: the opening tag, the content and the closing tag. The opening tag delimits the start of the formatted part, and can also carry some configuration options. Some opening tags, like the color one shown above, also require a value to work. Other opening tags may accept multiple options (separated by spaces within the opening tag). The closing tag delimits the end of the formatted part. In some cases, both the closing tag and the content can be omitted.

Unlike BBCode in HTML, leading/trailing whitespace is not removed by a RichTextLabel upon display. Duplicate spaces are also displayed as-is in the final output. This means that when displaying a code block in a RichTextLabel, you don’t need to use a preformatted text tag.

[tag]content[/tag]
[tag=value]content[/tag]
[tag option1=value1 option2=value2]content[/tag]
[tag][/tag]
[tag]

备注

RichTextLabel doesn’t support entangled BBCode tags. For example, instead of using:

[b]bold[i]bold italic[/b]italic[/i]

请使用：

[b]bold[i]bold italic[/i][/b][i]italic[/i]

安全地处理用户输入

In a scenario where users may freely input text (such as chat in a multiplayer game), you should make sure users cannot use arbitrary BBCode tags that will be parsed by RichTextLabel. This is to avoid inappropriate use of formatting, which can be problematic if [url] tags are handled by your RichTextLabel (as players may be able to create clickable links to phishing sites or similar).

Using RichTextLabel’s [lb] and/or [rb] tags, we can replace the opening and/or closing brackets of any BBCode tag in a message with those escaped tags. This prevents users from using BBCode that will be parsed as tags – instead, the BBCode will be displayed as text.

创建一个 Node 节点并附加下面的脚本：

extends RichTextLabel
func _ready():
    append_chat_line("Player 1", "Hello world!")
    append_chat_line("Player 2", "Hello [color=red]BBCode injection[/color] (no escaping)!")
    append_chat_line_escaped("Player 2", "Hello [color=red]BBCode injection[/color] (with escaping)!")
# Returns escaped BBCode that won't be parsed by RichTextLabel as tags.
func escape_bbcode(bbcode_text):
    # We only need to replace opening brackets to prevent tags from being parsed.
    return bbcode_text.replace("[", "[lb]")
# Appends the user's message as-is, without escaping. This is dangerous!
func append_chat_line(username, message):
    append_text("%s: [color=green]%s[/color]\n" % [username, message])
# Appends the user's message with escaping.
# Remember to escape both the player name and message contents.
func append_chat_line_escaped(username, message):
    append_text("%s: [color=green]%s[/color]\n" % [escape_bbcode(username), escape_bbcode(message)])

剥离 BBCode 标签

For certain use cases, it can be desired to remove BBCode tags from the string. This is useful when displaying the RichTextLabel’s text in another Control that does not support BBCode (such as a tooltip):

extends RichTextLabel
func _ready():
    var regex = RegEx.new()
    regex.compile("\\[.*?\\]")
    var text_without_tags = regex.sub(text, "", true)
    # `text_without_tags` contains the text with all BBCode tags removed.

备注

Removing BBCode tags entirely isn’t advised for user input, as it can modify the displayed text without users understanding why part of their message was removed. Escaping user input should be preferred instead.

性能

In most cases, you can use BBCode directly as-is since text formatting is rarely a heavy task. However, with particularly large RichTextLabels (such as console logs spanning thousands of lines), you may encounter stuttering during gameplay when the RichTextLabel’s text is updated.

There are several ways to alleviate this:

• Use the append_text() function instead of appending to the text property. This function will only parse BBCode for the added text, rather than parsing BBCode from the entire text property.

• Use push_[tag]() and pop() functions to add tags to RichTextLabel instead of using BBCode.

• Enable the Threading > Threaded property in RichTextLabel. This won’t speed up processing, but it will prevent the main thread from blocking, which avoids stuttering during gameplay. Only enable threading if it’s actually needed in your project, as threading has some overhead.

使用 push_[标签]() 和 pop() 函数代替 BBCode

If you don’t want to use BBCode for performance reasons, you can use functions provided by RichTextLabel to create formatting tags without writing BBCode in the text.

Every BBCode tag (including effects) has a push_[tag]() function (where [tag] is the tag’s name). There are also a few convenience functions available, such as push_bold_italics() that combines both push_bold() and push_italics() into a single tag. See the RichTextLabel class reference for a complete list of push_[tag]() functions.

The pop() function is used to end any tag. Since BBCode is a tag stack, using pop() will close the most recently started tags first.

The following script will result in the same visual output as using BBCode [color=green]test [i]example[/i][/color]:

extends RichTextLabel
func _ready():
    append_text("BBCode ")  # Trailing space separates words from each other.
    push_color(Color.GREEN)
    append_text("test ")  # Trailing space separates words from each other.
    push_italics()
    append_text("example")
    pop()  # Ends the tag opened by `push_italics()`.
    pop()  # Ends the tag opened by `push_color()`.

警告

Do not set the text property directly when using formatting functions. Appending to the text property will erase all modifications made to the RichTextLabel using the append_text(), push_[tag]() and pop() functions.

参考

参见

Some of these BBCode tags can be used in tooltips for @export script variables as well as in the XML source of the class reference. For more information, see Class reference BBCode.

备注

Tags for bold ([b]) and italics ([i]) formatting work best if the appropriate custom fonts are set up in the RichTextLabelNode’s theme overrides. If no custom bold or italic fonts are defined, faux bold and italic fonts will be generated by Godot. These fonts rarely look good in comparison to hand-made bold/italic font variants.

The monospaced ([code]) tag only works if a custom font is set up in the RichTextLabel node’s theme overrides. Otherwise, monospaced text will use the regular font.

目前还没有用于控制文本垂直居中的BBCode标签.

Options can be skipped for all tags.

段落选项

• align

  值	left (or l), center (or c), right (or r), fill (or f)
  默认	left

  文本水平对齐。

• bidi_override、st

  值	default (of d), uri (or u), file (or f), email (or e), list (or l), none (or n), custom (or c)
  默认	default

  Structured text override.

• justification_flags, jst

  值	Comma-separated list of the following values: kashida (or k), word (or w), trim (or tr), after_last_tab (or lt), skip_last (or sl), skip_last_with_chars (or sv), do_not_skip_single (or ns).
  默认	word,kashida,skip_last,do_not_skip_single

  Justification (fill alignment) option. See TextServer for more details.

• direction、dir

  值	ltr (or l), rtl (or r), auto (or a)
  默认	继承

  Base BiDi direction.

• language、lang

  值	ISO 语言代码。见 区域设置代码
  默认	继承

  Locale override. Some font files may contain script-specific substitutes, in which case they will be used.

• tab_stops

  值	List of floating-point numbers, e.g. 10.0,30.0
  默认	Width of the space character in the font

  Overrides the horizontal offsets for each tab character. When the end of the list is reached, the tab stops will loop over. For example, if you set tab_stops to 10.0,30.0, the first tab will be at 10 pixels, the second tab will be at 10 + 30 = 40 pixels, and the third tab will be at 10 + 30 + 10 = 50 pixels from the origin of the RichTextLabel.

处理 [url] 标签点击

默认情况下， [url] 标签在单击时不执行任何操作.这是为了允许灵活使用 [url] 标签，而不是限制它们在Web浏览器中打开URL.

To handle clicked [url] tags, connect the RichTextLabel node’s meta_clicked signal to a script function.

例如，将如下方法连接到 meta_clicked 上即可在用户的默认网页浏览器中打开被点击的 URL：

# This assumes RichTextLabel's `meta_clicked` signal was connected to
# the function below using the signal connection dialog.
func _richtextlabel_on_meta_clicked(meta):
    # `meta` is not guaranteed to be a String, so convert it to a String
    # to avoid script errors at run-time.
    OS.shell_open(str(meta))

要支持更高级的用法，也可以在 [url] 标签的选项中存储 JSON，然后在处理 meta_clicked 信号的函数中解析。例如：

[url={"example": "value"}]JSON[/url]

图像选项

• color

  值	颜色名称或十六进制格式的颜色
  默认	继承

  图像的着色颜色（调制）。

• height

  值	整数
  默认	继承

  Target height of the image in pixels, add % to the end of value to specify it as percentages of the control width instead of pixels.

• width

  值	整数
  默认	继承

  Target width of the image, add % to the end of value to specify it as percentages of the control width instead of pixels.

• region

  值	x,y,width,height in pixels
  默认	继承

  图像的区域框。可用于显示精灵表中的单个图像。

• pad

  值	false, true
  默认	false

  如果设为 true 且图像小于 width 和 height 指定的大小，那么就会为图像加上边距让大小一致，不会进行缩放。

• tootip

  值	字符串
  默认

  图像的工具提示。

图像和表格的垂直对齐

When a vertical alignment value is provided with the [img] or [table]` tag the image/table will try to align itself against the surrounding text. Alignment is performed using a vertical point of the image and a vertical point of the text. There are 3 possible points on the image (top, center, and bottom) and 4 possible points on the text and table (top, center, baseline, and bottom), which can be used in any combination.

To specify both points, use their full or short names as a value of the image/table tag:

text [img=top,bottom]...[/img] text
text [img=center,center]...[/img] text

text [table=3,center]...[/table] text  # Center to center.
text [table=3,top,bottom]...[/table] text # Top of the table to the bottom of text.
text [table=3,baseline,baseline,1]...[/table] text # Baseline of the second row (rows use zero-based indexing) to the baseline of text.

You can also specify just one value (top, center, or bottom) to make use of a corresponding preset (top-top, center-center, and bottom-bottom respectively).

Short names for the values are t (top), c (center), l (baseline), and b (bottom).

字体选项

• name、n

  值	有效的 Font 资源路径。
  默认	继承

  字体资源路径。

• size、s

  值	数字，单位为像素。
  默认	继承

  自定义字体大小。

• glyph_spacing、gl

  值	数字，单位为像素。
  默认	继承

  Extra spacing for each glyph.

• glyph_spacing、sp

  值	数字，单位为像素。
  默认	继承

  Extra spacing for the space character.

• top_spacing、top

  值	数字，单位为像素。
  默认	继承

  Extra spacing at the top of the line.

• bottom_spacing、bt

  值	数字，单位为像素。
  默认	继承

  Extra spacing at the bottom of the line.

• embolden、emb

  值	浮点数字。
  默认	0.0

  字体加粗强度，非零时会加粗字体的轮廓。负值会降低轮廓的粗细。

• face_index、fi

  值	整数。
  默认	0

  TrueType / OpenType 合集中活动字体的索引号。

• slant、sln

  值	浮点数字。
  默认	0.0

  字体倾斜强度，正值会将字形向右倾斜，负值会将字形向左倾斜。

• opentype_variation、otv

  值	OpenType 变体标签列表，使用英文逗号分隔。
  默认

  Font OpenType variation coordinates. See OpenType variation tags.

  Note: The value should be enclosed in " to allow using = inside it:

[font otv="wght=200,wdth=400"] # Sets variable font weight and width.

• opentype_features、otf

  值	OpenType 特性标签列表，使用英文逗号分隔。
  默认

  Font OpenType features. See OpenType features tags.

  Note: The value should be enclosed in " to allow using = inside it:

[font otf="calt=0,zero=1"] # Disable contextual alternates, enable slashed zero.

具名颜色

For tags that allow specifying a color by name you can use names of the constants from the built-in Color class. Named classes can be specified in a number of styles using different casings: DARK_RED, DarkRed, and darkred will give the same exact result.

十六进制颜色代码

For opaque RGB colors, any valid 6-digit hexadecimal code is supported, e.g. [color=#ffffff]white[/color]. Shorthand RGB color codes such as #6f2 (equivalent to #66ff22) are also supported.

For transparent RGB colors, any RGBA 8-digit hexadecimal code can be used, e.g. [color=#ffffff88]translucent white[/color]. Note that the alpha channel is the last component of the color code, not the first one. Short RGBA color codes such as #6f28 (equivalent to #66ff2288) are supported as well.

单元格选项

• expand

  值	整数
  默认	1

  单元格扩张比例。定义的是哪些单元格会尝试按比例扩展到其他单元格，以及相应的扩张比例。

• border

  值	颜色名称或十六进制格式的颜色
  默认	继承

  单元格边框颜色。

• bg

  值	颜色名称或十六进制格式的颜色
  默认	继承

  单元格背景色。如果想要单双行使用不同的背景色，请使用 bg=单行颜色,双行颜色。

• padding

  值	四个用英文逗号分隔的浮点数
  默认	0, 0, 0, 0

  单元格左侧、上方、右侧、下方的内边距。

无序列表项目符号

By default, the [ul] tag uses the U+2022 “Bullet” Unicode glyph as the bullet character. This behavior is similar to web browsers. The bullet character can be customized using [ul bullet={bullet}]. If provided, this {bullet} parameter must be a single character with no enclosing quotes (for example, [bullet=*]). Additional characters are ignored. The bullet character’s width does not affect the list’s formatting.

See Bullet (typography) on Wikipedia) for a list of common bullet characters that you can paste directly in the bullet parameter.

有序列表类型

Ordered lists can be used to automatically mark items with numbers or letters in ascending order. This tag supports the following type options:

• 1 - Numbers, using language specific numbering system if possible.

• a, A - Lower and upper case Latin letters.

• i, I - Lower and upper case Roman numerals.

文本效果

BBCode can also be used to create different text effects that can optionally be animated. Five customizable effects are provided out of the box, and you can easily create your own. By default, animated effects will pause when the SceneTree is paused. You can change this behavior by adjusting the RichTextLabel’s Process > Mode property.

All examples below mention the default values for options in the listed tag format.

备注

Text effects that move characters’ position may result in characters being clipped by the RichTextLabel node bounds.

You can resolve this by disabling Control > Layout > Clip Contents in the inspector after selecting the RichTextLabel node, or ensuring there is enough margin added around the text by using line breaks above and below the line using the effect.

脉冲

Pulse creates an animated pulsing effect that multiplies each character’s opacity and color. It can be used to bring attention to specific text. Its tag format is [pulse freq=1.0 color=#ffffff40 ease=-2.0]{text}[/pulse].

freq controls the frequency of the half-pulsing cycle (higher is faster). A full pulsing cycle takes 2 * (1.0 / freq) seconds. color is the target color multiplier for blinking. The default mostly fades out text, but not entirely. ease is the easing function exponent to use. Negative values provide in-out easing, which is why the default is -2.0.

波浪

Wave makes the text go up and down. Its tag format is [wave amp=50.0 freq=5.0 connected=1]{text}[/wave].

amp controls how high and low the effect goes, and freq controls how fast the text goes up and down. A freq value of 0 will result in no visible waves, and negative freq values won’t display any waves either. If connected is 1 (default), glyphs with ligatures will be moved together. If connected is 0, each glyph is moved individually even if they are joined by ligatures. This can work around certain rendering issues with font ligatures.

旋风

Tornado makes the text move around in a circle. Its tag format is [tornado radius=10.0 freq=1.0 connected=1]{text}[/tornado].

radius is the radius of the circle that controls the offset, freq is how fast the text moves in a circle. A freq value of 0 will pause the animation, while negative freq will play the animation backwards. If connected is 1 (default), glyphs with ligatures will be moved together. If connected is 0, each glyph is moved individually even if they are joined by ligatures. This can work around certain rendering issues with font ligatures.

抖动

Shake makes the text shake. Its tag format is [shake rate=20.0 level=5 connected=1]{text}[/shake].

rate controls how fast the text shakes, level controls how far the text is offset from the origin. If connected is 1 (default), glyphs with ligatures will be moved together. If connected is 0, each glyph is moved individually even if they are joined by ligatures. This can work around certain rendering issues with font ligatures.

渐隐

Fade creates a static fade effect that multiplies each character’s opacity. Its tag format is [fade start=4 length=14]{text}[/fade].

start controls the starting position of the falloff relative to where the fade command is inserted, length controls over how many characters should the fade out take place.

彩虹

Rainbow gives the text a rainbow color that changes over time. Its tag format is [rainbow freq=1.0 sat=0.8 val=0.8]{text}[/rainbow].

freq is the number of full rainbow cycles per second, sat is the saturation of the rainbow, val is the value of the rainbow. A freq value of 0 will pause the animation, while negative freq will play the animation backwards.

Font outlines are not affected by the rainbow effect (they keep their original color). Existing font colors are overridden by the rainbow effect. However, CanvasItem’s Modulate and Self Modulate properties will affect how the rainbow effect looks, as modulation multiplies its final colors.

自定义 BBCode 标签和文本效果

可以通过扩展 RichTextEffect 资源类型来创建自己的 BBCode 标签。首先扩展 RichTextEffect 资源类型并为脚本提供 class_name，这样就能够在检查器中选择该效果。如果想在编辑器中运行这些自定义效果，请在 GDScript 文件中添加 @tool 注解。RichTextLabel 不需要附加脚本，也不需要在 tool 模式下运行。注册效果的方法是将这个新建的效果在检查器中加入到 Markup > Custom Effects 数组中，或者在代码中使用 install_effect() 方法：

警告

If the custom effect is not registered within the RichTextLabel’s Markup > Custom Effects property, no effect will be visible and the original tag will be left as-is.

只需要扩展一个函数: _process_custom_fx(char_fx) , 或者可以通过添加成员名称 bbcode 来提供自定义BBCode标识符, 该代码将自动检查bbcode属性, 或使用文件名来决定BBCode标签应该是什么.

_process_custom_fx

This is where the logic of each effect takes place and is called once per glyph during the draw phase of text rendering. This passes in a CharFXTransform object, which holds a few variables to control how the associated glyph is rendered:

• identity身份 指定正在处理哪个自定义效果, 应该用它来控制代码流程.

• outline is true if effect is called for drawing text outline.

• range tells you how far into a given custom effect block you are in as an index.

• elapsed_time 是文本效果运行的总时间.

• visible will tell you whether the glyph is visible or not and will also allow you to hide a given portion of text.

• offset is an offset position relative to where the given glyph should render under normal circumstances.

• color is the color of a given glyph.

• glyph_index and font is glyph being drawn and font data resource used to draw it.

• Finally, env is a Dictionary of parameters assigned to a given custom effect. You can use get() with an optional default value to retrieve each parameter, if specified by the user. For example [custom_fx spread=0.5 color=#FFFF00]test[/custom_fx] would have a float spread and Color color parameters in its env Dictionary. See below for more usage examples.

The last thing to note about this function is that it is necessary to return a boolean true value to verify that the effect processed correctly. This way, if there’s a problem with rendering a given glyph, it will back out of rendering custom effects entirely until the user fixes whatever error cropped up in their custom effect logic.

以下是一些自定义效果的示例:

幽灵

@tool
extends RichTextEffect
class_name RichTextGhost
# Syntax: [ghost freq=5.0 span=10.0][/ghost]
# Define the tag name.
var bbcode = "ghost"
func _process_custom_fx(char_fx):
    # Get parameters, or use the provided default value if missing.
    var speed = char_fx.env.get("freq", 5.0)
    var span = char_fx.env.get("span", 10.0)
    var alpha = sin(char_fx.elapsed_time * speed + (char_fx.range.x / span)) * 0.5 + 0.5
    char_fx.color.a = alpha
    return true

矩阵

@tool
extends RichTextEffect
class_name RichTextMatrix
# Syntax: [matrix clean=2.0 dirty=1.0 span=50][/matrix]
# Define the tag name.
var bbcode = "matrix"
# Gets TextServer for retrieving font information.
func get_text_server():
    return TextServerManager.get_primary_interface()
func _process_custom_fx(char_fx):
    # Get parameters, or use the provided default value if missing.
    var clear_time = char_fx.env.get("clean", 2.0)
    var dirty_time = char_fx.env.get("dirty", 1.0)
    var text_span = char_fx.env.get("span", 50)
    var value = char_fx.glyph_index
    var matrix_time = fmod(char_fx.elapsed_time + (char_fx.range.x / float(text_span)), \
                           clear_time + dirty_time)
    matrix_time = 0.0 if matrix_time < clear_time else \
                  (matrix_time - clear_time) / dirty_time
    if matrix_time > 0.0:
        value = int(1 * matrix_time * (126 - 65))
        value %= (126 - 65)
        value += 65
    char_fx.glyph_index = get_text_server().font_get_glyph_index(char_fx.font, 1, value, 0)
    return true

这将增加一些新的BBCode命令, 可以像这样使用:

[center][ghost]This is a custom [matrix]effect[/matrix][/ghost] made in
[pulse freq=5.0 height=2.0][pulse color=#00FFAA freq=2.0]GDScript[/pulse][/pulse].[/center]