Correct cursor positioning+proper scrolling

editor.go

@@ -39,6 +39,9 @@ type Editor struct {
 	LinesHead *LinesNode
 	LineCount int
 
+	LineHeight float32
+	CharWidth  float32
+
 	StartPos float32
 }
 
@@ -51,6 +54,23 @@ func (e *Editor) SetStartPos(mouseDeltaNorm int32) {
 	e.StartPos = clampF32(e.StartPos+float32(-mouseDeltaNorm)*settings.ScrollSpeed, 0, float32(e.LineCount))
 }
 
+func (e *Editor) RefreshFontSettings() {
+	e.LineHeight = imgui.TextLineHeightWithSpacing()
+
+	//NOTE: Because of 'https://github.com/ocornut/imgui/issues/792', CalcTextSize returns slightly incorrect width
+	//values for sentences than to be expected with singleCharWidth*sentenceCharCount. For example, with 3 chars at width 10
+	//we expect width of 30 (for a fixed-width font), but instead we might get 29.
+	// This is fixed in the newer releases, but imgui-go hasn't updated yet.
+	//
+	//That's why instead of getting width of one char, we get the average width from the width of a sentence, which helps us position
+	//cursors properly for now
+	e.CharWidth = imgui.CalcTextSize("abcdefghijklmnopqrstuvwxyz", false, 1000).X / 26
+}
+
+func (e *Editor) RoundToNearestChar(x float32) float32 {
+	return float32(math.Round(float64(x/e.CharWidth))) * e.CharWidth
+}
+
 func (e *Editor) Render(drawStartPos, winSize *imgui.Vec2) {
 
 	//Draw window
@@ -67,52 +87,42 @@ func (e *Editor) Render(drawStartPos, winSize *imgui.Vec2) {
 	paddedDrawStartPos := *drawStartPos
 
 	//Draw lines
-	lineHeight := imgui.TextLineHeightWithSpacing()
+	linesToDraw := int(winSize.Y / e.LineHeight)
-	charWidth := imgui.CalcTextSize("a", false, 1000).X
-	linesToDraw := int(winSize.Y / lineHeight)
 	// println("Lines to draw:", linesToDraw)
 
 	dl := imgui.WindowDrawList()
 	startLine := clampInt(int(e.StartPos), 0, e.LineCount)
-	println("Start Pos: ", e.StartPos, "; Start line:", startLine)
 	for i := startLine; i < startLine+linesToDraw; i++ {
 		dl.AddText(*drawStartPos, imgui.PackedColorFromVec4(imgui.Vec4{X: 1, Y: 1, Z: 1, W: 1}), string(e.GetLine(0+i).chars))
-		drawStartPos.Y += lineHeight
+		drawStartPos.Y += e.LineHeight
 	}
 
-	//Draw cursor
+	//Calculate position of cursor in window and grid coords.
-	cx := clampInt(e.MouseX-int(paddedDrawStartPos.X), 0, int(winSize.X))
+	//Window coords are as reported by SDL, but we correct for padding and snap to the nearest
-	cy := clampInt(e.MouseY-int(paddedDrawStartPos.Y), 0, int(winSize.Y))
+	//char window pos.
+	//
+	//Since gopad only supports fixed-width fonts, we treat the text area as a grid with each
+	//cell having identical width and one char.
+	clickedColWindowY := clampInt(e.MouseY-int(paddedDrawStartPos.Y), 0, math.MaxInt)
+	clickedColGridY := clampInt(clickedColWindowY/int(e.LineHeight), 0, e.LineCount)
 
-	clickedLine := clampInt(cy/int(lineHeight), 0, e.LineCount)
+	clickedColWindowX := clampInt(int(e.RoundToNearestChar(float32(e.MouseX))), 0, math.MaxInt)
-	clickedCol := cx / int(charWidth)
+	clickedColGridX := clickedColWindowX / int(e.CharWidth)
-	// fmt.Printf("line,col: %v,%v\n", clickedLine, clickedCol)
 
-	eee := e.GetLine(clickedLine)
+	clickedLine := e.GetLine(startLine + clickedColGridY)
-	tabCount, tabChars := getTabs(eee, clickedCol)
+	tabCount, _ := getTabs(clickedLine, clickedColGridX)
 
-	maxCol := len(eee.chars) - 1
+	textWidth := float32(len(clickedLine.chars)-tabCount+tabCount*settings.TabSize) * e.CharWidth
-	if tabCount > 0 {
+	lineX := clampF32(float32(clickedColWindowX), 0, paddedDrawStartPos.X+textWidth)
-		maxCol += clampInt(tabCount*settings.TabSize, 0, math.MaxInt)
-	}
-	finalCol := clampInt(clickedCol+tabChars, 0, maxCol)
-	// if len(eee.chars) > 0 && finalCol > 0 {
-	// 	x := finalCol - tabCount*settings.TabSize
-	// 	println("!!!!", len(string(eee.chars)), "; C:", string(eee.chars[x]))
-	// }
-
-	lineX := paddedDrawStartPos.X + float32(finalCol)*charWidth
 	lineStart := imgui.Vec2{
 		X: lineX,
-		Y: paddedDrawStartPos.Y + float32(clickedLine)*lineHeight - lineHeight*0.25,
+		Y: paddedDrawStartPos.Y + float32(clickedColGridY)*e.LineHeight - e.LineHeight*0.25,
 	}
 	lineEnd := imgui.Vec2{
 		X: lineX,
-		Y: paddedDrawStartPos.Y + float32(clickedLine)*lineHeight + lineHeight*0.75,
+		Y: paddedDrawStartPos.Y + float32(clickedColGridY)*e.LineHeight + e.LineHeight*0.75,
 	}
-
+	dl.AddLineV(lineStart, lineEnd, imgui.PackedColorFromVec4(imgui.Vec4{Z: 0.7, W: 1}), settings.CursorWidthFactor*e.CharWidth)
-	thickness := 0.2 * charWidth
-	dl.AddLineV(lineStart, lineEnd, imgui.PackedColorFromVec4(imgui.Vec4{Z: 0.7, W: 1}), thickness)
 }
 
 func getTabs(l *Line, col int) (tabCount, charsToOffsetBy int) {
@@ -247,6 +257,7 @@ func NewScratchEditor() *Editor {
 		FileName:  "**scratch**",
 		LinesHead: NewLineNode(),
 	}
+
 	return e
 }
 

go.mod

@@ -3,12 +3,13 @@ module github.com/bloeys/gopad
 go 1.17
 
 require (
-	github.com/bloeys/nmage v0.0.8
+	github.com/bloeys/nmage v0.0.10
 	github.com/inkyblackness/imgui-go/v4 v4.3.0
 	github.com/veandco/go-sdl2 v0.4.14
 )
 
 require (
+	github.com/bloeys/assimp-go v0.4.2 // indirect
 	github.com/bloeys/gglm v0.3.1 // indirect
 	github.com/go-gl/gl v0.0.0-20211210172815-726fda9656d6 // indirect
 )

go.sum

@@ -1,8 +1,13 @@
+github.com/bloeys/assimp-go v0.4.2 h1:ArVK74BCFcTO/rCGj2NgZG9xtbjnJdEn5npIeJx1Z04=
 github.com/bloeys/assimp-go v0.4.2/go.mod h1:my3yRxT7CfOztmvi+0svmwbaqw0KFrxaHxncoyaEIP0=
 github.com/bloeys/gglm v0.3.1 h1:Sy9upW7SBsBfDXrSmEhid3aQ+7J7itej+upwcxOnPMQ=
 github.com/bloeys/gglm v0.3.1/go.mod h1:qwJQ0WzV191wAMwlGicbfbChbKoSedMk7gFFX6GnyOk=
 github.com/bloeys/nmage v0.0.8 h1:HCoEaTBWTucnXrjQ+8OCUTzG/3rjpV1eliXWUW44+FY=
 github.com/bloeys/nmage v0.0.8/go.mod h1:4h2tKtMvk9ab8r/+rem4QonPXEBTho6VWvpCMm0M6iM=
+github.com/bloeys/nmage v0.0.9 h1:dP0g8e7VeygbX5AcYLTIPheLJr+CZmG2uOICQfcDTDA=
+github.com/bloeys/nmage v0.0.9/go.mod h1:4h2tKtMvk9ab8r/+rem4QonPXEBTho6VWvpCMm0M6iM=
+github.com/bloeys/nmage v0.0.10 h1:6Ryl3qjEbXxeIL+9BnBxOrGaW9mKObyY/JbRYkR8ogQ=
+github.com/bloeys/nmage v0.0.10/go.mod h1:4h2tKtMvk9ab8r/+rem4QonPXEBTho6VWvpCMm0M6iM=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-gl/gl v0.0.0-20211025173605-bda47ffaa784/go.mod h1:9YTyiznxEY1fVinfM7RvRcjRHbw2xLBJ3AAGIT0I4Nw=

main.go

@@ -6,9 +6,11 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/bloeys/gopad/settings"
 	"github.com/bloeys/nmage/engine"
 	"github.com/bloeys/nmage/input"
 	"github.com/bloeys/nmage/logging"
+	"github.com/bloeys/nmage/renderer/rend3dgl"
 	nmageimgui "github.com/bloeys/nmage/ui/imgui"
 	"github.com/inkyblackness/imgui-go/v4"
 	"github.com/veandco/go-sdl2/sdl"
@@ -56,7 +58,7 @@ func main() {
 		panic(err)
 	}
 
-	window, err := engine.CreateOpenGLWindowCentered("nMage", 1280, 720, engine.WindowFlags_RESIZABLE|engine.WindowFlags_ALLOW_HIGHDPI)
+	window, err := engine.CreateOpenGLWindowCentered("nMage", 1280, 720, engine.WindowFlags_RESIZABLE|engine.WindowFlags_ALLOW_HIGHDPI, rend3dgl.NewRend3DGL())
 	if err != nil {
 		logging.ErrLog.Fatalln("Failed to create window. Err: ", err)
 	}
@@ -86,13 +88,12 @@ func (g *Gopad) Init() {
 	g.Win.EventCallbacks = append(g.Win.EventCallbacks, g.handleWindowEvents)
 
 	//Setup font
-	var fontSize float32 = 16
 	fConfig := imgui.NewFontConfig()
 	defer fConfig.Delete()
 
 	fConfig.SetOversampleH(2)
 	fConfig.SetOversampleV(2)
-	g.mainFont = g.ImGUIInfo.AddFontTTF("./res/fonts/courier-prime.regular.ttf", fontSize, &fConfig, nil)
+	g.mainFont = g.ImGUIInfo.AddFontTTF("./res/fonts/courier-prime.regular.ttf", settings.FontSize, &fConfig, nil)
 
 	//Sidebar
 	g.CurrDirContents = getDirContents(g.CurrDir)
@@ -121,6 +122,15 @@ func (g *Gopad) Init() {
 	g.activeEditor = len(g.editors) - 1
 }
 
+func (g *Gopad) Start() {
+	imgui.PushFont(g.mainFont)
+	for i := 0; i < len(g.editors); i++ {
+		e := &g.editors[i]
+		e.RefreshFontSettings()
+	}
+	imgui.PopFont()
+}
+
 func (g *Gopad) handleWindowEvents(event sdl.Event) {
 
 	switch e := event.(type) {
@@ -361,7 +371,8 @@ func (g *Gopad) getActiveEditor() *Editor {
 func (g *Gopad) getEditor(index int) *Editor {
 
 	if len(g.editors) == 0 {
-		e := Editor{FileName: "**scratch**"}
+		e := *NewScratchEditor()
+		e.RefreshFontSettings()
 		g.editors = append(g.editors, e)
 		g.activeEditor = 0
 		return &e
@@ -420,7 +431,9 @@ func (g *Gopad) handleFileClick(fPath string) {
 	}
 
 	//Read new file and switch to it
-	g.editors = append(g.editors, *NewEditor(fPath))
+	e := *NewEditor(fPath)
+	e.RefreshFontSettings()
+	g.editors = append(g.editors, e)
 	g.activeEditor = len(g.editors) - 1
 }
 

settings/settings.go

@@ -3,8 +3,10 @@ package settings
 import "github.com/inkyblackness/imgui-go/v4"
 
 var (
+	FontSize           float32    = 16
 	TextSelectionColor imgui.Vec4 = imgui.Vec4{X: 84 / 255.0, Y: 153 / 255.0, Z: 199 / 255.0, W: 0.4}
 	EditorBgColor      imgui.Vec4 = imgui.Vec4{X: 0.1, Y: 0.1, Z: 0.1, W: 1}
 	TabSize            int        = 4
 	ScrollSpeed        float32    = 4
+	CursorWidthFactor  float32    = 0.15
 )