Bitmap font support in Corona SDK, compatible with Graphics 2.0

bmf.lua

module( ..., package.seeall )

-- AngelCode bitmap font support
-- Updated for Graphics 2.0

-- Download sprite module from https://github.com/coronalabs/framework-sprite-legacy/raw/master/sprite.lua
local sprite = require( "sprite" )

-- Specify an Angelcode format bitmap font definition file (".FNT")
-- The spritesheet(s) that this file references need to be located in the resource directory.
-- Return value is a font object that can be used when calling newString
function loadFont( fntFile, path )
    local function extract( s, p )
        return string.match( s, p ), string.gsub( s, p, '', 1 )
    end
    local path = path or ""
    local font = { info = {}, spritesheets = {}, sprites = {}, chars = {}, kernings = {} }
    local readline = io.lines( system.pathForFile( path .. fntFile, system.ResourceDirectory ) )
    for line in readline do
        local t = {}; local tag;
        tag, line = extract( line, '^%s*([%a_]+)%s*' )
        while string.len( line ) > 0 do
            local k, v
            k, line = extract( line, '^([%a_]+)=' )
            if not k then
                break
            end
            v, line = extract( line, '^"([^"]*)"%s*' )
            if not v then
                v, line = extract( line, '^([^%s]*)%s*' )
            end
            if not v then
                break
            end
            t[ k ] = v
        end
        if tag == 'info' or tag == 'common' then
            for k, v in pairs( t ) do font.info[ k ] = v end
        elseif tag == 'page' then
            font.spritesheets[ 1 + t.id ] = { file = t.file, frames = {} }
        elseif tag == 'char' then
            t.letter = string.char( t.id )
            font.chars[ t.letter ] = {}
            for k, v in pairs( t ) do font.chars[ t.letter ][ k ] = v end
            if 0 + font.chars[ t.letter ].width > 0 and 0 + font.chars[ t.letter ].height > 0 then
                font.spritesheets[ 1 + t.page ].frames[ #font.spritesheets[ 1 + t.page ].frames + 1 ] = {
                    --textureRect = { x = 0 + t.x, y = 0 + t.y, width = -1 + t.width, height = -1 + t.height }, --CLF removed the -1, it was causing issues with fonts with borders
                    textureRect = { x = 0 + t.x, y = 0 + t.y, width = t.width, height = t.height },
                    spriteSourceSize = { width = 0 + t.width, height = 0 + t.height },
                    spriteColorRect = { x = 0, y = 0, width = -1 + t.width, height = -1 + t.height },
                    spriteTrimmed = true
                }
                font.sprites[ t.letter ] = {
                    spritesheet = 1 + t.page,
                    frame = #font.spritesheets[ 1 + t.page ].frames
                }
            end
        elseif( tag == 'kerning' ) then
            font.kernings[ string.char( t.first ) .. string.char( t.second ) ] = 0 + t.amount
        end
    end
    for k, v in pairs( font.spritesheets ) do
        font.spritesheets[ k ].sheet = sprite.newSpriteSheetFromData( path..v.file, v )
    end
    for k, v in pairs( font.sprites ) do
        font.sprites[ k ] = sprite.newSpriteSet( font.spritesheets[ v.spritesheet ].sheet, v.frame, 1 )
    end
    return font
end

-- extend an object with accessor behaviors
local function accessorize( t )
    local mt = getmetatable( t )
    setmetatable( t, {
        __index = function( t, k )
            if rawget( t, 'get_'..k ) then
                return rawget(t, 'get_'..k )( t, k )
            elseif rawget( t, 'raw_'..k ) then
                return rawget( t, 'raw_'..k )
            elseif mt.__index then
                return mt.__index( t, k )
            else
                return nil
            end
        end,
        __newindex = function( t, k, v )
            if rawget( t, 'set_'..k ) then
                rawget( t, 'set_'..k )( t, k, v )
            elseif rawget( t, 'raw_'..k ) then
                rawset( t, 'raw_'..k, v )
            elseif mt.__newindex then
                mt.__newindex( t, k, v )
            else
                rawset( t, 'raw_'..k, v )
            end
        end,
    } )
end

-- extend an object with cascading removeSelf
local function removerize( t )
    local old = t.removeSelf
    t.removeSelf = function( o )
        for i = o.numChildren, 1, -1 do o[ i ]:removeSelf() end
        old( o )
    end
end

-- Pass a font object (obtained from loadFont) and a string to render
-- Return value is a DisplayObject of the rendered string
-- object.font can be read/modifed
-- object.text can be read/modified
-- object.align can be read/modified - left/right/center (multiline not yet fully supported for non-left)
-- object.input( function(text), { filter = function(), max = 32 } )
-- turns the object into a text input.
-- the callback is hit when the user presses "return" or the field losed focus.
-- this code is under development - more documentation will be added soon...
function newString( font, text ,origsize, newsize)
    
    local finalScale  = 100/origsize *newsize/100;
    local obj = display.newGroup()
    accessorize( obj )
    removerize( obj )
    
    obj.set_font = function( t, k, v )
        obj.raw_font = v
        if t.text then
            t.text = t.text
        end
    end
    
    -- Set the alignment of the object
    obj.set_align = function( t, k, v )
        local w = t.textWidth
        if t.raw_align == 'right' then
            for i = 1, t.numChildren do
                t[ i ].x = t[ i ].x + w
            end
        elseif t.raw_align == 'center' then
            for i = 1, t.numChildren do
                t[ i ].x = t[ i ].x + math.floor( w * 0.5 )
            end
        end
        t.raw_align = v
        if t.raw_align == 'right' then
            for i = 1, t.numChildren do
                t[ i ].x = t[ i ].x - w
            end
        elseif t.raw_align == 'center' then
            for i = 1, t.numChildren do
                t[ i ].x = t[ i ].x - math.floor( w * 0.5 )                
            end
        elseif t.raw_align ~= 'left' then
            t.raw_align = 'left'
        end
    end
    
    -- Set the text for the object
    obj.set_text = function( t, k, v )
        if ( v == t.raw_text ) then
            return
        end
        t.raw_text = v
        for i = t.numChildren, 1, -1 do
            t[i]:removeSelf()
        end
        local oldAlign = ( t.align or 'left' )
        t.align = 'left'
        local x = 0; local y = 0
        local last = ''; local xMax = 0; local yMax = 0
        if t.raw_font then
            for c in string.gmatch( t.raw_text..'\n', '(.)' ) do
                if c == '\n' then
                    x = 0; y = y + t.raw_font.info.lineHeight
                    if y >= yMax then
                        yMax = y
                    end
                elseif t.raw_font.chars[ c ] then
                    local rfc = t.raw_font.chars[ c ]
                    if 0 + t.raw_font.chars[ c ].width > 0 and 0 + t.raw_font.chars[ c ].height > 0 then
                        local letter = sprite.newSprite( t.raw_font.sprites[ c ] )
                        if t.raw_font.kernings[ last .. c ] then
                            x = x + font.kernings[ last .. c ]
                        end
                        t:insert( letter )
                        letter.anchorX = 0
                        letter.anchorY = 0
                        letter.x = t.raw_font.chars[ c ].xoffset + x
                        letter.y = t.raw_font.chars[ c ].yoffset - t.raw_font.info.base + y
                        last = c
                    end
                    --x = x + t.raw_font.chars[ c ].xadvance
                    x = x + t.raw_font.chars[ c ].xadvance + (t.raw_font.info.outline or 0) --CLF added support for outlines
                    if x >= xMax then
                        xMax = x
                    end                    
                end
            end
            obj.textWidth = xMax
            local background = display.newRect( 0, -t.raw_font.info.base, xMax, yMax )
            background.isBackground = true --CLF Added to support tinting of font.
            obj:insert( background )
            background:setFillColor( 0, 0, 0, 0 )
        end
        t.align = oldAlign        
    end
    
    obj.input = function( f, args )
        -- spawn the text field invisibly
        local field
        -- Handle character insertion/deletion
        local function char()
            -- check if any character has been added or deleted
            if field.text ~= '--' then
                if string.len( field.text ) < 2 then
                    -- backspace was pressed
                    if string.len( obj.text ) > 0 then
                        obj.text = string.sub( obj.text, 1, -2 )
                    end
                else
                    -- some other key was pressed
                    obj.text = obj.text..string.sub( field.text, 3 )
                end
                field.text = '--'
                if args.filter then
                    obj.text = string.sub( args.filter( obj.text ), 1, (args.max or 32) )
                else
                    obj.text = string.sub( obj.text, 1, (args.max or 32) )
                end
            end
        end
        Runtime:addEventListener( 'enterFrame', char )
        -- Handle the "done" phase
        local function done( e )
            if e.phase == 'submitted' or e.phase == 'ended' then
                native.setKeyboardFocus( nil )
                field:removeSelf()
                Runtime:removeEventListener( 'enterFrame', char )
                f( text )
            end
        end
        field = native.newTextField( 0, 0, 240, 24, done )
        field.text = '--'
        field.isVisible = false
        native.setKeyboardFocus( field )
    end
    obj.font = font
    obj.align = 'left'
    obj.text = (text or '')
    
    obj.xScale = finalScale;
    obj.yScale = finalScale;

    return obj
end

function newParagraph(font, text, width)
    local obj = display.newGroup()
    accessorize( obj )
    removerize( obj )
    
    obj.set_font = function( t, k, v )
        obj.raw_font = v
        --if t.text then t.text = t.text end
    end
    
    obj.set_paragraphWidth = function( t, k, v )
        obj.raw_paragraphWidth = v
        --if t.text then t.text = t.text end
    end
    
    obj.set_tint = function( t, k, v )
        obj.raw_tint = v
        for i = t.numChildren, 1, -1 do
            for j = t[i].numChildren, 1, -1 do
                if(not t[i][j].isBackground) then
                    if v[4] then
                        t[i][j]:setFillColor(v[1],v[2],v[3],v[4])
                    else
                        t[i][j]:setFillColor(v[1],v[2],v[3])
                    end
                end
            end
        end
        --if t.text then t.text = t.text end
    end
    
    obj.set_text = function(t, k, v)
        --save the new raw text
        t.raw_text = v
        
        --remove all children
        for i = t.numChildren, 1, -1 do
            t[i]:removeSelf()
        end
        
        --determine the width of a space
        local space = bmf.newString(font, " ")
        local spaceWidth = space.raw_font.info.outline*-1 or 0
        space:removeSelf()
        space = nil
        
        --Create our word-wrapped paragraph.
        local spaceLeft = t.raw_paragraphWidth
        local x, y = obj.x, obj.y
        
        for word, spacer in string.gmatch(v, "([^%s%-]+)([%s%-]*)") do
            local w = bmf.newString(font, word..spacer)
            if(w.width + spaceWidth) > spaceLeft then
                spaceLeft = t.raw_paragraphWidth - w.width - spaceWidth
                y = y + w.raw_font.info.lineHeight
                x = obj.x
                w.x = x
            else
                w.x = x + t.raw_paragraphWidth - spaceLeft
                spaceLeft = spaceLeft - w.width - spaceWidth
            end
            
            w.y = y
            
            obj:insert(w)
        end
    end
    
    obj.paragraphWidth = width or display.viewableContentWidth
    obj.text = text
    obj.font = font
    obj.tint = {255,255,255}
    
    return obj
end