Add text example with anchor controls

ext/text/gui/gui.go

@@ -0,0 +1,165 @@
+package gui
+
+import (
+	"image/png"
+	"path/filepath"
+	"runtime"
+
+	"github.com/gopxl/pixel/v2"
+	"github.com/gopxl/pixel/v2/backends/opengl"
+	"github.com/gopxl/pixel/v2/ext/atlas"
+	"github.com/gopxl/pixelui/v2"
+	"github.com/inkyblackness/imgui-go/v4"
+)
+
+var basepath string = getBasepath()
+
+type MenuOptions struct {
+	Padding pixel.Vec
+	Height  float64
+
+	SetAnchor   func(anchor pixel.Anchor)
+	UnsetAnchor func()
+	Reset       func()
+}
+
+func NewMenu(win *opengl.Window, textures *atlas.Atlas, options MenuOptions) *Menu {
+	basepath = getBasepath()
+	var (
+		topLeft     = filepath.Join(basepath, "assets/anchor_button_top_left.png")
+		top         = filepath.Join(basepath, "assets/anchor_button_top.png")
+		topRight    = filepath.Join(basepath, "assets/anchor_button_top_right.png")
+		left        = filepath.Join(basepath, "assets/anchor_button_left.png")
+		center      = filepath.Join(basepath, "assets/anchor_button_center.png")
+		right       = filepath.Join(basepath, "assets/anchor_button_right.png")
+		bottomLeft  = filepath.Join(basepath, "assets/anchor_button_bottom_left.png")
+		bottom      = filepath.Join(basepath, "assets/anchor_button_bottom.png")
+		bottomRight = filepath.Join(basepath, "assets/anchor_button_bottom_right.png")
+	)
+	if options.Height == 0 {
+		options.Height = 32
+	}
+
+	guiGroup := textures.MakeGroup()
+	menu := &Menu{
+		win:     win,
+		options: options,
+		anchorButtons: []*anchorButton{
+			// Pixel anchors describe the direction in which the anchored item will me moved,
+			// so we take the opposite in order to describe the position of the anchor itself.
+			{guiGroup.AddFile(topLeft, png.Decode), pixel.TopLeft.Opposite()},
+			{guiGroup.AddFile(top, png.Decode), pixel.Top.Opposite()},
+			{guiGroup.AddFile(topRight, png.Decode), pixel.TopRight.Opposite()},
+			{guiGroup.AddFile(left, png.Decode), pixel.Left.Opposite()},
+			{guiGroup.AddFile(center, png.Decode), pixel.Center},
+			{guiGroup.AddFile(right, png.Decode), pixel.Right.Opposite()},
+			{guiGroup.AddFile(bottomLeft, png.Decode), pixel.BottomLeft.Opposite()},
+			{guiGroup.AddFile(bottom, png.Decode), pixel.Bottom.Opposite()},
+			{guiGroup.AddFile(bottomRight, png.Decode), pixel.BottomRight.Opposite()},
+		},
+	}
+	textures.Pack()
+	return menu
+}
+
+// Menu has controls anchoring and reseting text
+type Menu struct {
+	win     *opengl.Window
+	options MenuOptions
+
+	anchorButtons []*anchorButton
+	selected      *anchorButton
+}
+
+// Update is called every frame to redraw UI elements in the window
+func (m *Menu) Update() {
+	imgui.PushStyleVarVec2(imgui.StyleVarWindowPadding, pixelui.IVec(m.options.Padding))
+	imgui.SetNextWindowPos(pixelui.IVec(pixel.V(0, 0)))
+	imgui.SetNextWindowSize(pixelui.IVec(m.size()))
+	imgui.BeginV("Menu", nil, imgui.WindowFlagsNoDecoration)
+	{
+		m.anchorDropdown()
+		m.resetButton()
+	}
+	imgui.End()
+	imgui.PopStyleVarV(1)
+}
+
+func (m *Menu) size() pixel.Vec {
+	return pixel.V(m.win.Bounds().Size().X, m.options.Height)
+}
+
+func (m *Menu) buttonHeight() float32 {
+	return float32(m.options.Height - 2*m.options.Padding.Y)
+}
+
+// anchorDropdown manages the anchor button popup window
+func (m *Menu) anchorDropdown() {
+	size := imgui.Vec2{X: 64, Y: m.buttonHeight()}
+	imgui.ButtonV("Anchor", size)
+	imgui.SetNextWindowPos(imgui.Vec2{X: float32(m.options.Padding.X), Y: float32(m.options.Padding.Y) + size.Y + 4})
+	imgui.OpenPopupOnItemClickV("Anchors", 0)
+	if imgui.BeginPopup("Anchors") {
+		for i, anchorButton := range m.anchorButtons {
+			if i%3 != 0 {
+				imgui.SameLineV(0, 4)
+			}
+			active := anchorButton == m.selected
+			if anchorButton.add(active) {
+				if active {
+					m.selected = nil
+					m.options.UnsetAnchor()
+				} else {
+					m.selected = anchorButton
+					m.options.SetAnchor(anchorButton.anchor)
+				}
+			}
+		}
+		imgui.EndPopup()
+	}
+}
+
+func (m *Menu) resetButton() {
+	size := imgui.Vec2{X: 48, Y: m.buttonHeight()}
+	imgui.SameLine()
+	imgui.PushStyleColor(imgui.StyleColorButton, pixelui.ColorA(255, 0, 0, 200))
+	imgui.PushStyleColor(imgui.StyleColorButtonHovered, pixelui.ColorA(220, 0, 0, 200))
+	imgui.PushStyleColor(imgui.StyleColorButtonActive, pixelui.ColorA(175, 0, 0, 200))
+	if imgui.ButtonV("Reset", size) {
+		m.selected = nil
+		m.options.Reset()
+	}
+	imgui.PopStyleColorV(3)
+}
+
+type anchorButton struct {
+	textureId atlas.TextureId
+	anchor    pixel.Anchor
+}
+
+func (ab *anchorButton) add(active bool) bool {
+	var color imgui.Vec4
+	if active {
+		color = pixelui.ColorA(255, 255, 255, 100)
+	} else {
+		color = pixelui.Color(255, 255, 255)
+	}
+
+	if imgui.ImageButtonV(
+		imgui.TextureID(ab.textureId.ID()),
+		pixelui.IVec(ab.textureId.Bounds().Size()),
+		imgui.Vec2{X: 0, Y: 0},
+		imgui.Vec2{X: 1, Y: 1},
+		0,
+		imgui.Vec4{X: 0, Y: 0, Z: 0, W: 0},
+		color,
+	) {
+		return true
+	}
+	return false
+}
+
+func getBasepath() string {
+	_, b, _, _ := runtime.Caller(0)
+	return filepath.ToSlash(filepath.Dir(filepath.Dir(b)))
+}