[devtools] Implement distance measurement

Author: elgopher

devtools/internal/inspector/draw.go

@@ -15,18 +15,16 @@ import (
 
 var BgColor, FgColor byte
 
+var pixelColorAtMouseCoords byte
+
 func Draw() {
 	snapshot.Draw()
-
-	// I check the input in Draw function because only during Draw operation
-	// I have access to screen restored from snapshot
-	if pi.MouseBtnp(pi.MouseLeft) {
-		x, y := pi.MousePos()
-		fmt.Printf("Screen pixel (%d, %d) with color %d selected\n", x, y, pi.Pget(x, y))
-	}
-
+	pixelColorAtMouseCoords = pi.Pget(pi.MousePos())
 	moveBarIfNeeded()
 	drawBar()
+
+	drawDistanceLine()
+
 	drawPointer()
 }
 
@@ -39,9 +37,15 @@ func drawBar() {
 
 	pi.RectFill(0, barY, vm.ScreenWidth, barY+6, BgColor)
 
-	mostX := printCoords(mouseX, mouseY, 1, barY+1)
-	color := pi.Pget(mouseX, mouseY)
-	printPixelColor(color, mostX+4, barY+1)
+	textX := 1
+	textY := barY + 1
+
+	if distance.measuring {
+		printDistance(textX, textY)
+	} else {
+		mostX := printCoords(mouseX, mouseY, textX, textY)
+		printPixelColor(pixelColorAtMouseCoords, mostX+4, textY)
+	}
 }
 
 func printCoords(mouseX int, mouseY int, x, y int) int {
@@ -60,10 +64,27 @@ func drawPointer() {
 }
 
 func choosePointerColor(x, y int) byte {
-	c := pi.Pget(x, y)
+	c := pixelColorAtMouseCoords
 	if rgb.BrightnessDelta(vm.Palette[FgColor], vm.Palette[c]) >= rgb.BrightnessDelta(vm.Palette[BgColor], vm.Palette[c]) {
 		return FgColor
 	}
 
 	return BgColor
 }
+
+func drawDistanceLine() {
+	if distance.measuring {
+		x, y := pi.MousePos()
+		pi.Line(distance.startX, distance.startY, x, y, BgColor)
+	}
+}
+
+func printDistance(x, y int) int {
+	if distance.measuring {
+		dist, width, height := calcDistance()
+		text := fmt.Sprintf("D: %.1f W: %d H: %d", dist, width, height)
+		return pi.Print(text, x, y, FgColor)
+	}
+
+	return x
+}

devtools/internal/inspector/update.go

@@ -0,0 +1,43 @@
+package inspector
+
+import (
+	"fmt"
+	"math"
+
+	"github.com/elgopher/pi"
+)
+
+var distance struct {
+	measuring      bool
+	startX, startY int
+}
+
+func calcDistance() (dist float64, width, height int) {
+	x, y := pi.MousePos()
+
+	width = x - distance.startX
+	if width < 0 {
+		width *= -1
+	}
+
+	height = y - distance.startY
+	if height < 0 {
+		height *= -1
+	}
+	dist = math.Sqrt(float64(width*width + height*height))
+	return
+}
+
+func Update() {
+	x, y := pi.MousePos()
+
+	if pi.MouseBtn(pi.MouseLeft) && !distance.measuring {
+		distance.measuring = true
+		distance.startX, distance.startY = x, y
+		fmt.Printf("Measuring started at (%d, %d)\n", x, y)
+	} else if !pi.MouseBtn(pi.MouseLeft) && distance.measuring {
+		distance.measuring = false
+		dist, width, height := calcDistance()
+		fmt.Printf("Measuring stopped at (%d, %d). Distance is: %f, width: %d, height %d\n", x, y, dist, width, height)
+	}
+}

devtools/update.go

@@ -3,7 +3,10 @@
 
 package devtools
 
-import "github.com/elgopher/pi/key"
+import (
+	"github.com/elgopher/pi/devtools/internal/inspector"
+	"github.com/elgopher/pi/key"
+)
 
 func updateDevTools() {
 	if key.Btnp(key.F12) {
@@ -13,4 +16,8 @@ func updateDevTools() {
 			resumeGame()
 		}
 	}
+
+	if gamePaused {
+		inspector.Update()
+	}
 }