examples/text/text_ttf_loading.lua
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--
--  raylib [text] example - TTF loading and usage
--
--  This example has been created using raylib 1.6 (www.raylib.com)
--  raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
--
--  Copyright (c) 2014-2016 Ramon Santamaria (@raysan5)
--
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-- Initialization
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local screenWidth = 800;
local screenHeight = 450;

InitWindow(screenWidth, screenHeight, "raylib [text] example - ttf loading")

local msg = "TTF SpriteFont"

-- NOTE: Textures/Fonts MUST be loaded after Window initialization (OpenGL context is required)

-- TTF SpriteFont loading with custom generation parameters
local font = LoadFontEx("resources/KAISG.ttf", 96, 0, 0)

-- Generate mipmap levels to use trilinear filtering
-- NOTE: On 2D drawing it won't be noticeable, it looks like FILTER_BILINEAR
--font.texture = GenTextureMipmaps(font.texture) -- ISSUE: attempt to index a SpriteFont value (local 'font')

local fontSize = font.baseSize
local fontPosition = Vector2(40, screenHeight/2 + 50)
local textSize

SetTextureFilter(font.texture, FILTER_POINT)
local currentFontFilter = 0      -- Default: FILTER_POINT

local count = 0
local droppedFiles

SetTargetFPS(60)
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-- Main game loop
while not WindowShouldClose() do            -- Detect window close button or ESC key
    -- Update
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    fontSize = fontSize + GetMouseWheelMove()*4.0

    -- Choose font texture filter method
    if (IsKeyPressed(KEY_ONE)) then
        SetTextureFilter(font.texture, FILTER_POINT)
        currentFontFilter = 0
    elseif (IsKeyPressed(KEY_TWO)) then
        SetTextureFilter(font.texture, FILTER_BILINEAR)
        currentFontFilter = 1
    elseif (IsKeyPressed(KEY_THREE)) then
        -- NOTE: Trilinear filter won't be noticed on 2D drawing
        SetTextureFilter(font.texture, FILTER_TRILINEAR)
        currentFontFilter = 2
    end

    textSize = MeasureTextEx(font, msg, fontSize, 0)

    if (IsKeyDown(KEY_LEFT)) then fontPosition.x = fontPosition.x - 10
    elseif (IsKeyDown(KEY_RIGHT)) then fontPosition.x = fontPosition.x + 10
    end

    -- Load a dropped TTF file dynamically (at current fontSize)
    if (IsFileDropped()) then
        droppedFiles = GetDroppedFiles()
        count = #droppedFiles

        if (count == 1) then -- Only support one ttf file dropped
            UnloadSpriteFont(font)
            font = LoadFontTTF(droppedFiles[1], fontSize, 0, 0)
            ClearDroppedFiles()
        end
    end
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    -- Draw
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    BeginDrawing()

        ClearBackground(RAYWHITE)

        DrawText("Use mouse wheel to change font size", 20, 20, 10, GRAY)
        DrawText("Use KEY_RIGHT and KEY_LEFT to move text", 20, 40, 10, GRAY)
        DrawText("Use 1, 2, 3 to change texture filter", 20, 60, 10, GRAY)
        DrawText("Drop a new TTF font for dynamic loading", 20, 80, 10, DARKGRAY)

        DrawTextEx(font, msg, fontPosition, fontSize, 0, BLACK)

        -- TODO: It seems texSize measurement is not accurate due to chars offsets...
        --DrawRectangleLines(fontPosition.x, fontPosition.y, textSize.x, textSize.y, RED)

        DrawRectangle(0, screenHeight - 80, screenWidth, 80, LIGHTGRAY)
        DrawText(string.format("Font size: %02.02f", fontSize), 20, screenHeight - 50, 10, DARKGRAY)
        DrawText(string.format("Text size: [%02.02f, %02.02f]", textSize.x, textSize.y), 20, screenHeight - 30, 10, DARKGRAY)
        DrawText("CURRENT TEXTURE FILTER:", 250, 400, 20, GRAY)

        if (currentFontFilter == 0) then DrawText("POINT", 570, 400, 20, BLACK)
        elseif (currentFontFilter == 1) then DrawText("BILINEAR", 570, 400, 20, BLACK)
        elseif (currentFontFilter == 2) then DrawText("TRILINEAR", 570, 400, 20, BLACK)
        end

    EndDrawing()
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end

-- De-Initialization
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UnloadSpriteFont(font)     -- SpriteFont unloading

ClearDroppedFiles()        -- Clear internal buffers

CloseWindow()               -- Close window and OpenGL context
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