ImGui Examples

Here you will find various resources to help you create GUI with Dear ImGui in Gideros Studio.

note: you may have to provide your own assets (fonts, gfx, …).

ImGui Custom Font

require "ImGui"

-- imgui
self.imgui = ImGui.new()
-- imgui font
local imguiio = self.imgui:getIO()
local fontatlas = imguiio:getFonts()
local myfont = fontatlas:addFont("fonts/Cabin-Regular-TTF.ttf", 22) -- your custom font here
imguiio:setFontDefault(myfont)
fontatlas:build()
-- imgui style
local imguistyle = self.imgui:getStyle()
imguistyle:setWindowMinSize(64*4, 96) -- 64*6, 96

ImGui Centered Text & Colored Text

Here we center our text and introduce some more functionalities

require "ImGui"

local imgui = ImGui.new()
stage:addChild(imgui)
-- some imgui params
local IO = imgui:getIO()
IO:setFontGlobalScale(2.5)
--imgui:setLightStyle()
--imgui:setClassicStyle()
-- some vars
local xtext, xtext2 = "Centered Text", "Colored Text"

-- the loop
function enterFrame(e)
	local CW = application:getContentWidth()
	
	-- 1 begin
	imgui:newFrame(e.deltaTime)
	
	-- 2 our GUI
	if (imgui:beginFullScreenWindow("Hello ImGui", nil)) then
		-- some spacing
		imgui:dummy(CW, 32 * 2) -- imgui:dummy(w, h)
		-- a centered text
		local textW = imgui:calcTextSize(xtext)
		local textMid = (CW - textW) / 2
		imgui:dummy(textMid, 0)
		imgui:sameLine(0, 0) -- puts the next element on the same line with no gap, for gaps use imgui:sameLine()
		imgui:text(xtext)
		-- some spacing
		imgui:dummy(CW, 32 * 4)
		-- a colored text
		imgui:textColored(xtext2, 0xff00ff)
		imgui:endWindow()

		-- 3 end
	end
	imgui:endFrame()
	imgui:render()
end

-- the listeners
stage:addEventListener("enterFrame", enterFrame)

ImGui Buttons

Here we make some buttons

require "ImGui"
-- Setup ImGui
local imgui = ImGui.new()
stage:addChild(imgui)
-- some imgui params
local IO = imgui:getIO()
IO:setFontGlobalScale(2.5)

imgui:setClassicStyle()

stage:addChild(imgui)

-- some vars
local xtext = "Centered Text"

-- image to draw
local imageTex = Texture.new("gfx/image.jpg")

function enterFrame(e)
	-- 1 begin
	imgui:newFrame(e.deltaTime)

	local CW = application:getContentWidth()
	-- 2 our GUI
	if (imgui:beginFullScreenWindow("Hello ImGui", nil)) then
		-- some spacing
		imgui:dummy(CW, 32 * 2)
		-- a centered text?
		local textW = imgui:calcTextSize(xtext)
		local textMid = (CW - textW) / 2
		imgui:dummy(textMid, 0) 
		imgui:sameLine(0, 0) 
		imgui:text(xtext)
		-- some spacing
		imgui:dummy(CW, 32 * 2)
		-- a button
		imgui:text("A button")
		imgui:pushStyleVar(ImGui.StyleVar_ButtonTextAlign, 0.5, 0.5)
		imgui:button(("x"), 128, 64) -- text, w, h
		imgui:popStyleVar()
		-- some spacing
		imgui:dummy(CW, 32 * 1)
		-- a grid of buttons
		imgui:text("A grid of buttons")
		
		local i = 0
		for x = 0,1,0.5 do
			for y = 0,1,0.5 do
				imgui:pushStyleVar(ImGui.StyleVar_ButtonTextAlign, x, y)
				if(imgui:button(("[%.1f, %.1f]"):format(x,y), application:getContentWidth() / 3, 100)) then
					print(x, y)
				end
				imgui:popStyleVar()
				-- count elements
				i += 1
				-- make new line on 3d element
				if (i % 3 ~= 0) then imgui:sameLine() end
			end
		end
		-- some spacing
		imgui:dummy(application:getContentWidth(), 32 * 1)
		-- an image button with text
		imgui:text("An image button \nwith text")
		if(imgui:imageButtonWithText(imageTex, "button", 16, 16)) then
			print("pressed")
		end
	end
	
	imgui:endWindow()

	-- 3 end
	imgui:endFrame()
	imgui:render()
end
-- add listener to draw GUI
stage:addEventListener("enterFrame", enterFrame)

File open/save dialog project example

GitHub

ImGui Snap to Grid

Here is a grid snaped window snippet

require "ImGui"

GRID_CELL @ 64
application:setBackgroundColor(0x323232)
local CW = application:getContentWidth()
local CH = application:getContentHeight()

for i = 1, CW, GRID_CELL do
	local line = Pixel.new(0xffffff, 1, 1, CH)
	line:setX(i)
	stage:addChild(line)
end

for i = 1, CH, GRID_CELL do
	local line = Pixel.new(0xffffff, 1, CW, 1)
	line:setY(i)
	stage:addChild(line)
end

local imgui = ImGui.new()
stage:addChild(imgui)
local mainWindowOpen, drawMainWindowOpen = true, false
local snapX,snapY = 0, 0
local offsetX, offsetY = 0, 0
local dragFlag = false

local function myResizeCallback(x,y,cw,ch,dw,dh)
	return (dw // GRID_CELL) * GRID_CELL, (dh // GRID_CELL) * GRID_CELL
end

function enterFrame(e)
	imgui:newFrame(e.deltaTime)
	if (mainWindowOpen) then
		imgui:setNextWindowPos(snapX, snapY)
		imgui:setNextWindowSizeConstraints(GRID_CELL*2, GRID_CELL*1, GRID_CELL*8, GRID_CELL*8)
		mainWindowOpen, drawMainWindowOpen = imgui:beginWindow("My window", mainWindowOpen, nil, myResizeCallback)
		local mouseClicked = imgui:isMouseClicked(KeyCode.MOUSE_LEFT)
		if not dragFlag and mouseClicked and imgui:isWindowHovered() then dragFlag=true end
		if imgui:isWindowFocused() and dragFlag then
			local mx,my = imgui:getMousePos()
			local wx, wy = imgui:getWindowPos()
			if mouseClicked or imgui:isMouseReleased(KeyCode.MOUSE_LEFT) then
				offsetX, offsetY = mx - wx, my - wy
			end
			if imgui:isMouseDragging(KeyCode.MOUSE_LEFT, 0) then
				snapX = ((mx - offsetX) // GRID_CELL) * GRID_CELL
				snapY = ((my - offsetY) // GRID_CELL) * GRID_CELL
			else
				dragFlag = false
			end
		end
		if (drawMainWindowOpen) then 
			-- do stuff
		end
		imgui:endWindow()
	end
	imgui:endFrame()
	imgui:render()
end

stage:addEventListener("mouseDown", function(e) imgui:onMouseDown(e) end)
stage:addEventListener("mouseUp", function(e) imgui:onMouseUp(e) end)
stage:addEventListener("mouseHover", function(e) imgui:onMouseHover(e) end)
stage:addEventListener("mouseMove", function(e) imgui:onMouseMove(e) end)
stage:addEventListener("mouseWheel", function(e) imgui:onMouseWheel(e) end)
stage:addEventListener("keyDown", function(e) imgui:onKeyDown(e) end)
stage:addEventListener("keyUp", function(e) imgui:onKeyUp(e) end)
stage:addEventListener("keyChar", function(e) imgui:onKeyChar(e) end)
stage:addEventListener("enterFrame", enterFrame)

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