Fixed width fonts specific management

This commit is contained in:
Pierre-Yves Rollo 2018-12-05 11:42:36 +01:00
parent a3e0d36a68
commit b71d5a8f01
3 changed files with 121 additions and 62 deletions

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@ -7,35 +7,84 @@ Name of the font to be used when no font is given. The font should be registered
If no default\_font given or if default\_font given but not registered, the first registered font will be used as default.
## Provided methods
## Use font_api with display_api (to display text on nodes)
### Base setup
Font_api offers a direct integration with display_api to display text on nodes.
First of all, create a display node with an entity.
To do this, refer to API.md in display_api mod, in particular "Howto register a display node".
The only requirement then is to connect the `on_display_update` callback of the display entity to `font_api.on_display_update`:
```
minetest.register_node("mymod:test_text_node", {
...
paramtype2 = "facedir",
...
groups = { display_api = 1, ... },
...
display_entities = {
["mymod:text"] = {
depth = -0.5 - display_api.entity_spacing,
on_display_update = font_api.on_display_update },
}
...
on_place = display_api.on_place,
on_construct = display_api.on_construct,
on_destruct = display_api.on_destruct,
on_rotate = display_api.on_rotate,
...
})
```
At this step, your node already displays text form "display_text" (hardcoded) node meta.
But it uses defaults (default font, default size, default color). Likely you need something more.
### Style your text
Font style and size can be chosen by adding some more entries to the display_entities definition table.
#### Font size
Font size can be defined in various ways (maybe more in the future).
Start with a number of lines, and font_api will make it fit to the entity size.
* `maxlines` or `lines`: Number of maximum lines of text to be displayed. The font height will be adjusted accordingly.
Then specify the char width. Two methods available:
* `aspect_ratio`: Defines the aspect ratio of chars. Works with all fonts. Should not be used if `columns` is specified.
* `columns`: Only if using a fixed width font, specifies the number of columns to display.
#### Font style
* `font_name`: name of the font to use. Should correspond to a registered font (from a font mod). If not specified or font not found, default font is used.
* `color`: color to be used (default black).
* `halign`: Horizontal alignment: "left", "center" or "right" (default "center").
* `valign`: Vertical alignement: "top", "middle" or "bottom" (default "middle").
## Provided methods
### font_api.get_default_font_name()
Returns de default font name.
### font_api.register_font(font_name, font_def)
Register a new font.
**font_name**: Name of the font to register. If registering different sizes of the same font, add size in the font name (e.g. times_10, times_12...).
**font_def**: Font definition table (see **Font definition table** below).
* `font_name`: Name of the font to register. If registering different sizes of the same font, add size in the font name (e.g. times_10, times_12...).
* `font_def`: Font definition table (see **Font definition table** below).
### font_api.on_display_update(pos, objref)
Standard on_display_update entity callback.
**pos**: Node position
**objref**: Object reference of entity
* `pos`: Node position
* `objref`: Object reference of entity
Node should have a corresponding display_entity with size, resolution and maxlines fields and optionally halign, valign and color fields.
### Font definition table
Font definition table used by **font_api.register_font** and **font\_api.Font:new** may/can contain following elements:
* **height** (required): Font height in pixels (all font textures should have the same height) .
* **widths** (required): Array of character widths in pixels, indexed by UTF codepoints.
* **margintop** (optional): Margin (in texture pixels) added on top of each char texture.
* **marginbottom** (optional): Margin (in texture pixels) added at bottom of each char texture.
* **linespacing** (optional): Spacing (in texture pixels) between each lines.
* `height` (required): Font height in pixels (all font textures should have the same height) .
* `widths` (required): Array of character widths in pixels, indexed by UTF codepoints.
* `margintop` (optional): Margin (in texture pixels) added on top of each char texture.
* `marginbottom` (optional): Margin (in texture pixels) added at bottom of each char texture.
* `linespacing` (optional): Spacing (in texture pixels) between each lines.
**margintop**, **marginbottom** and **linespacing** can be negative numbers (default 0) and are to be used to adjust various font styles to each other.
`margintop`, `marginbottom` and `linespacing` can be negative numbers (default 0) and are to be used to adjust various font styles to each other.
Font must have a char 0 which will be used to display any unknown char.
@ -57,7 +106,7 @@ Still in early stage of development, these tools are helpers to create font mods
### make_font_texture.sh
This scripts takes a .ttf file as input and create one .png file per char, that can be used as font texture. Launch it from your future font mod directory.
This scripts takes a .ttf file as input and create one .png file per char, that can be used as font texture. Launch it from your future font mod directory.
__Advice__
@ -95,51 +144,34 @@ __Syntax__
A font usable with font API. This class is supposed to be for internal use but who knows.
### font\_api.Font:new(def)
Create a new font object.
Create a new font object.
* `def` is a table containing font definition. See **Font definition table** above.
**def** is a table containing font definition. See **Font definition table** above.
### font:get_char_width(char)
Returns the width of char **char** in texture pixels.
**char**: Unicode codepoint of char.
### font:get_char_width(codepoint)
Returns the width of char `codepoint` in texture pixels.
* `codepoint`: Unicode codepoint of char.
### font:get_height(nb_of_lines)
Returns line(s) height. Takes care of top and bottom margins and line spacing.
**nb_of_lines**: Number of lines in the text.
* `nb_of_lines`: Number of lines in the text.
### font:get_width(line)
Returns the width of a text line. Beware, if line contains any new line char, they are ignored.
**line**: Line of text which the width will be computed.
* `line`: Line of text which the width will be computed.
### font:make_line_texture(line, texturew, x, y)
Create a texture for a text line.
**line**: Line of text to be rendered in texture.
**texturew**: Width of the texture (extra text is not rendered).
**x**: Starting x position in texture.
**y**: Vertical position of the line in texture.
* `line`: Line of text to be rendered in texture.
* `texturew`: Width of the texture (extra text is not rendered).
* `x`: Starting x position in texture.
* `y`: Vertical position of the line in texture.
### font:make_text_texture(text, texturew, textureh, maxlines, halign, valign, color)
Builds texture for a multiline colored text.
**text**: Text to be rendered.
**texturew**: Width of the texture (extra text will be truncated).
**textureh**: Height of the texture.
**maxlines**: Maximum number of lines.
**halign**: Horizontal text align ("left"/"center"/"right") (optional).
**valign**: Vertical text align ("top"/"center"/"bottom") (optional).
**color**: Color of the text (optional).
* `text`: Text to be rendered.
* `texturew`: Width of the texture (extra text will be truncated).
* `textureh`: Height of the texture.
* `maxlines`: Maximum number of lines.
* `halign`: Horizontal text align ("left"/"center"/"right") (optional).
* `valign`: Vertical text align ("top"/"center"/"bottom") (optional).
* `color`: Color of the text (optional).

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@ -103,6 +103,16 @@ function Font:new(def)
local font = table.copy(def)
setmetatable(font, self)
self.__index = self
-- Check if fixedwidth
for codepoint, width in pairs(font.widths) do
font.fixedwidth = font.fixedwidth or width
if width ~= font.fixedwidth then
font.fixedwidth = nil
break
end
end
return font
end
@ -138,11 +148,11 @@ end
--- Returns the width of a given char
-- @param char : codepoint of the char
-- @return Char width
function Font:get_char_width(char)
-- Replace chars with no texture by the NULL(0) char
if self.widths[char] ~= nil then
return self.widths[char]
function Font:get_char_width(codepoint)
if self.fixedwidth then
return self.fixedwidth
elseif self.widths[codepoint] then
return self.widths[codepoint]
else
return self.widths[0]
end
@ -201,12 +211,12 @@ function Font:make_line_texture(line, texturew, x, y)
codepoint, line = self:get_next_char(line)
-- Add image only if it is visible (at least partly)
if x + self.widths[codepoint] >= 0 and x <= texturew then
if x + self:get_char_width(codepoint) >= 0 and x <= texturew then
texture = texture..
string.format(":%d,%d=font_%s_%04x.png",
x, y, self.name, codepoint)
end
x = x + self.widths[codepoint]
x = x + self:get_char_width(codepoint)
end
return texture
@ -223,7 +233,7 @@ end
-- @return Texture string
function Font:make_text_texture(text, texturew, textureh, maxlines,
halign, valign, color)
halign, valign, color)
local texture = ""
local lines = {}
local textheight = 0

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@ -48,13 +48,30 @@ function font_api.on_display_update(pos, objref)
local font = font_api.get_font(meta:get_string("font") ~= ""
and meta:get_string("font") or def.font_name)
local maxlines = def.maxlines or 1 -- TODO:How to do w/o maxlines ?
-- Compute entity resolution accroding to given attributes
local texturew, textureh
textureh = font:get_height(def.lines or def.maxlines or 1)
if def.columns then
if font.fixedwidth then
texturew = def.columns * font.fixedwidth
if def.aspect_ratio then
minetest.log('warning', "[font_api] 'aspect_ratio' ignored because 'columns' is specified")
end
else
minetest.log('warning', "[font_api] 'columns' ignored because '"..font.name.."' is not a fixed width font.")
end
end
if not texturew then
if not def.aspect_ratio then
minetest.log('warning', "[font_api] No 'aspect_ratio' specified, using default 1.")
end
texturew = textureh * def.size.x / def.size.y / (def.aspect_ratio or 1)
end
objref:set_properties({
textures={font:make_text_texture(text,
font:get_height(maxlines) * def.size.x / def.size.y
/ (def.aspect_ratio or 1),
font:get_height(maxlines),
textures={font:make_text_texture(text, texturew, textureh,
def.maxlines, def.halign, def.valign, def.color)},
visual_size = def.size
})