Support panning around canvas

.gitignore

@@ -1,2 +1,4 @@
 .idea
 *.sh
+dist
+edbit

application/application.go

@@ -1,15 +1,21 @@
 package application
 
 import (
+	"errors"
 	"fmt"
 	"image"
 	"image/color"
+	"image/gif"
+	"image/jpeg"
+	"image/png"
+	"log"
 	"math"
 	"os"
-
-	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
+	"strings"
 
 	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
+	"golang.org/x/image/bmp"
 	"golang.org/x/image/colornames"
 )
 
@@ -22,6 +28,8 @@ type Application struct {
 
 	canvases []*canvas
 
+	active int
+
 	spinnerIndex int
 
 	hoverImg *ebiten.Image
@@ -30,35 +38,95 @@ type Application struct {
 }
 
 func NewApplication() *Application {
-	a := &Application{
+	app := &Application{
 		op: &ebiten.DrawImageOptions{},
 	}
 
-	a.addCanvas(8, 8)
+	app.addNewCanvas(8, 8)
 
-	a.canvases[0].img.Fill(colornames.Purple)
+	c := app.activeCanvas()
+	c.img.Fill(colornames.Purple)
+	c.scale = 256
 
-	a.activeCanvas().scale = 256
-	a.hoverImg = ebiten.NewImage(int(a.canvases[0].scale), int(a.canvases[0].scale)) // TODO
-	a.drawHoverImage()
+	app.drawHoverImage()
 
-	return a
+	return app
 }
 
-func (app *Application) addCanvas(w, h int) {
+func (app *Application) readFile(p string) (image.Image, error) {
+	f, err := os.OpenFile(p, os.O_RDONLY, 0600)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer f.Close()
+	p = strings.ToLower(p)
+	if strings.HasSuffix(p, ".bmp") {
+		img, err := bmp.Decode(f)
+		if err != nil {
+			log.Fatalf("failed to decode BMP file: %s", err)
+		}
+		return img, nil
+	} else if strings.HasSuffix(p, ".gif") {
+		img, err := gif.Decode(f)
+		if err != nil {
+			log.Fatalf("failed to decode GIF file: %s", err)
+		}
+		return img, nil
+	} else if strings.HasSuffix(p, ".jpg") || strings.HasSuffix(p, ".jpeg") {
+		img, err := jpeg.Decode(f)
+		if err != nil {
+			log.Fatalf("failed to decode JPG file: %s", err)
+		}
+		return img, nil
+	} else if strings.HasSuffix(p, ".png") {
+		img, err := png.Decode(f)
+		if err != nil {
+			log.Fatalf("failed to decode PNG file: %s", err)
+		}
+		return img, nil
+	} else if strings.HasSuffix(p, ".tff") || strings.HasSuffix(p, ".tiff") {
+		img, err := png.Decode(f)
+		if err != nil {
+			log.Fatalf("failed to decode PNG file: %s", err)
+		}
+		return img, nil
+	}
+	return nil, errors.New("unknown image format")
+}
+
+func (app *Application) OpenFile(p string) {
+	img, err := app.readFile(p)
+	if err != nil {
+		log.Fatal(err)
+	}
+	c := NewCanvas(img.Bounds().Dx(), img.Bounds().Dy())
+	c.img = ebiten.NewImageFromImage(img)
+	app.addCanvas(c)
+}
+
+func (app *Application) addCanvas(c *canvas) {
+	app.canvases = append(app.canvases, c)
+	app.active++
+
+	app.drawHoverImage()
+}
+
+func (app *Application) addNewCanvas(w, h int) {
 	c := NewCanvas(w, h)
 	app.canvases = append(app.canvases, c)
+
+	app.drawHoverImage()
 }
 
 func (app *Application) activeCanvas() *canvas {
-	return app.canvases[0]
+	return app.canvases[app.active]
 }
 
 func (app *Application) screenToCanvas(x, y int) (int, int) {
 	c := app.activeCanvas()
-
-	cx, cy := int(float64(x)/c.scale), int(float64(y)/c.scale)
-	return cx, cy
+	cx, cy := float64(x)/c.scale, float64(y)/c.scale
+	cx, cy = cx+c.x, cy+c.y
+	return int(cx), int(cy)
 }
 
 func (app *Application) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) {
@@ -86,20 +154,22 @@ func (app *Application) Update() error {
 			scroll = 1
 		}
 
-		offset := scroll * (app.canvases[0].scale / 7)
-		app.canvases[0].scale += offset
-		if app.canvases[0].scale < .001 {
-			app.canvases[0].scale = .001
-		} else if app.canvases[0].scale > 1000 {
-			app.canvases[0].scale = 1000
+		c := app.activeCanvas()
+
+		offset := scroll * (c.scale / 7)
+		c.scale += offset
+		if c.scale < .001 {
+			c.scale = .001
+		} else if c.scale > 1000 {
+			c.scale = 1000
 		}
 
-		hoverSize := int(math.Ceil(app.canvases[0].scale))
-		if hoverSize < 1 {
-			hoverSize = 1
+		if c.scale > 10 {
+			c.scale = float64(int(c.scale))
+		} else {
+			c.scale = math.Trunc(c.scale*10000) / 10000
 		}
-		hoverSize += 2
-		app.hoverImg = ebiten.NewImage(hoverSize, hoverSize)
+
 		app.drawHoverImage()
 	}
 
@@ -111,29 +181,43 @@ func (app *Application) Update() error {
 		c.img.Set(cx, cy, colornames.White)
 	}
 
+	c := app.activeCanvas()
+	panSize := 2 / c.scale
+	if ebiten.IsKeyPressed(ebiten.KeyRight) {
+		c.x += panSize
+	}
+	if ebiten.IsKeyPressed(ebiten.KeyLeft) {
+		c.x -= panSize
+	}
+	if ebiten.IsKeyPressed(ebiten.KeyUp) {
+		c.y -= panSize
+	}
+	if ebiten.IsKeyPressed(ebiten.KeyDown) {
+		c.y += panSize
+	}
 	return nil
 }
 
 func (app *Application) Draw(screen *ebiten.Image) {
-	// TODO translate and scale by camera pos
+	// Draw canvas.
 	c := app.activeCanvas()
 	app.op.GeoM.Reset()
+	app.op.GeoM.Translate(-c.x, -c.y)
 	app.op.GeoM.Scale(c.scale, c.scale)
 	screen.DrawImage(c.img, app.op)
 
+	// Draw hover outline.
 	cx, cy := app.screenToCanvas(app.cursorX, app.cursorY)
 	p := c.pixelScreenRect(cx, cy)
-
 	app.op.GeoM.Reset()
-	app.op.GeoM.Translate(float64(p.Min.X)-1, float64(p.Min.Y)-1)
+	app.op.GeoM.Translate(float64(p.Min.X), float64(p.Min.Y))
 	screen.DrawImage(app.hoverImg, app.op)
 
+	// Print debug information.
 	debugInfo := fmt.Sprintf("SCA %0.2f\nFPS %c %0.0f", app.activeCanvas().scale, spinner[app.spinnerIndex], ebiten.CurrentFPS())
-
 	debugBox := image.NewRGBA(image.Rect(10, 20, 200, 200))
 	debugImg := ebiten.NewImageFromImage(debugBox)
 	ebitenutil.DebugPrint(debugImg, debugInfo)
-
 	app.op.GeoM.Reset()
 	app.op.GeoM.Translate(3, 0)
 	app.op.GeoM.Scale(2, 2)
@@ -146,6 +230,15 @@ func (app *Application) Draw(screen *ebiten.Image) {
 }
 
 func (app *Application) drawHoverImage() {
+	c := app.activeCanvas()
+	hoverImgSize := int(c.scale)
+	if hoverImgSize < 1 {
+		hoverImgSize = 1
+	}
+	if app.hoverImg == nil || app.hoverImg.Bounds().Dx() != hoverImgSize || app.hoverImg.Bounds().Dy() != hoverImgSize {
+		app.hoverImg = ebiten.NewImage(hoverImgSize, hoverImgSize)
+	}
+
 	var colorWhite bool
 	nextColor := func() color.Color {
 		colorWhite = !colorWhite
@@ -160,24 +253,24 @@ func (app *Application) drawHoverImage() {
 	img.Clear()
 	bounds := img.Bounds()
 
-	hoverSize := 2
+	outlineWidth := 2
 	if app.activeCanvas().scale >= 1000 {
-		hoverSize = 6
+		outlineWidth = 6
 	} else if app.activeCanvas().scale >= 200 {
-		hoverSize = 5
+		outlineWidth = 5
 	} else if app.activeCanvas().scale >= 100 {
-		hoverSize = 4
+		outlineWidth = 4
 	} else if app.activeCanvas().scale >= 10 {
-		hoverSize = 3
+		outlineWidth = 3
 	}
-	for y := 0; y < hoverSize; y++ {
+	for y := 0; y < outlineWidth; y++ {
 		for x := 0; x < bounds.Max.X; x++ {
 			c := nextColor()
 			img.Set(x, bounds.Min.Y+y, c)
 			img.Set(x, bounds.Max.Y-y, c)
 		}
 	}
-	for x := 0; x < hoverSize; x++ {
+	for x := 0; x < outlineWidth; x++ {
 		for y := 0; y < bounds.Max.Y; y++ {
 			c := nextColor()
 			img.Set(bounds.Min.X+x, y, c)

application/canvas.go

@@ -10,6 +10,8 @@ import (
 type canvas struct {
 	w, h int
 
+	x, y float64 // View position
+
 	img *ebiten.Image
 
 	scale float64
@@ -25,5 +27,7 @@ func NewCanvas(w, h int) *canvas {
 }
 
 func (c *canvas) pixelScreenRect(x, y int) image.Rectangle {
-	return image.Rect(int(math.Floor(float64(x)*c.scale)), int(math.Floor(float64(y)*c.scale)), int(math.Ceil(float64(x+1)*c.scale)), int(math.Ceil(float64(y+1)*c.scale)))
+	rx, ry := (float64(x)-c.x)*c.scale, (float64(y)-c.y)*c.scale
+	rxCorner, ryCorner := (float64(x+1)-c.x)*c.scale, (float64(y+1)-c.y)*c.scale
+	return image.Rect(int(math.Floor(rx)), int(math.Floor(ry)), int(math.Ceil(rxCorner)), int(math.Ceil(ryCorner)))
 }

flags.go

@@ -0,0 +1,40 @@
+//go:build !js && !wasm
+// +build !js,!wasm
+
+package main
+
+import (
+	"flag"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"code.rocketnine.space/tslocum/edbit/application"
+)
+
+func parseFlags(app *application.Application) {
+	flag.Parse()
+
+	args := flag.Args()
+	for _, p := range args {
+		if strings.TrimSpace(p) == "" {
+			continue
+		}
+
+		if p == "~" {
+			dir, err := os.UserHomeDir()
+			if err != nil {
+				log.Fatal(err)
+			}
+			p = dir
+		} else if strings.HasPrefix(p, "~/") {
+			dir, err := os.UserHomeDir()
+			if err != nil {
+				log.Fatal(err)
+			}
+			p = filepath.Join(dir, p[2:])
+		}
+		app.OpenFile(p)
+	}
+}

flags_web.go

@@ -0,0 +1,12 @@
+//go:build js || wasm
+// +build js wasm
+
+package main
+
+import (
+	"code.rocketnine.space/tslocum/edbit/application"
+)
+
+func parseFlags(app *application.Application) {
+	// Do nothing
+}

goreleaser.yml

@@ -0,0 +1,31 @@
+project_name: edbit
+
+builds:
+  -
+    id: edbit
+#    ldflags:
+#      - -s -w -X code.rocketnine.space/tslocum/edbit/main.Version={{.Version}}
+    goos:
+      - js
+      - linux
+      - windows
+    goarch:
+      - amd64
+      - wasm
+archives:
+  -
+    id: edbit
+    builds:
+      - edbit
+    replacements:
+      386: i386
+    format_overrides:
+      - goos: js
+        format: zip
+      - goos: windows
+        format: zip
+    files:
+      - ./*.md
+      - LICENSE
+checksum:
+  name_template: 'checksums.txt'

main.go

@@ -42,6 +42,8 @@ func main() {
 		app.Exit()
 	}()
 
+	parseFlags(app)
+
 	if err := ebiten.RunGame(app); err != nil {
 		log.Fatal(err)
 	}