cmd/view-fits: zoom-in/zoom-out images

First stab at implementing zooming-in and zooming-out images.

Updates #17.

cmd/view-fits/main.go

@@ -39,6 +39,7 @@ import (
 	"strings"
 
 	"github.com/astrogo/fitsio"
+	"github.com/nfnt/resize"
 
 	"golang.org/x/exp/shiny/driver"
 	"golang.org/x/exp/shiny/screen"
@@ -89,6 +90,8 @@ Controls:
 
 Mouse controls:
 - Left button:       pan image
+- Wheel-Up:          increase zoom-level by 20%%
+- Wheel-Down:        decrease zoom-level by 20%%
 `)
 	}
 
@@ -192,14 +195,17 @@ Mouse controls:
 					}
 
 				case mouse.ButtonRight:
+					// no-op
+
 				case mouse.ButtonWheelDown:
-					if e.Direction == mouse.DirPress {
+					if e.Direction == mouse.DirStep {
 						ctrlZoomOut(&infos[cur.file].Images[cur.img], &repaint)
 					}
 				case mouse.ButtonWheelUp:
-					if e.Direction == mouse.DirPress {
+					if e.Direction == mouse.DirStep {
 						ctrlZoomIn(&infos[cur.file].Images[cur.img], &repaint)
 					}
+
 				}
 
 				if panning {
@@ -223,16 +229,11 @@ Mouse controls:
 						continue
 					}
 
-				case key.CodeKeypadPlusSign:
+				case key.CodeKeypadPlusSign, key.CodeEqualSign:
 					if e.Direction == key.DirPress {
 						ctrlZoomIn(&infos[cur.file].Images[cur.img], &repaint)
 					}
 
-				case key.CodeEqualSign:
-					if e.Direction == key.DirPress && e.Modifiers&key.ModShift != 0 {
-						ctrlZoomIn(&infos[cur.file].Images[cur.img], &repaint)
-					}
-
 				case key.CodeHyphenMinus:
 					if e.Direction == key.DirPress {
 						ctrlZoomOut(&infos[cur.file].Images[cur.img], &repaint)
@@ -329,16 +330,17 @@ Mouse controls:
 				img := infos[cur.file].Images[cur.img]
 
 				release(b)
-				b, err = s.NewBuffer(img.Bounds().Size())
+				curImg := img.get()
+				b, err = s.NewBuffer(curImg.Bounds().Size())
 				if err != nil {
 					log.Fatal(err)
 				}
 				defer release(b)
 
-				draw.Draw(b.RGBA(), b.Bounds(), img, img.orig, draw.Src)
+				draw.Draw(b.RGBA(), b.Bounds(), curImg, img.orig, draw.Src)
 
 				w.Fill(sz.Bounds(), bkg, draw.Src)
-				w.Upload(image.Point{}, b, img.Bounds())
+				w.Upload(image.Point{}, b, curImg.Bounds())
 				w.Publish()
 			}
 
@@ -464,6 +466,15 @@ func ctrlZoomIn(img *imageInfo, repaint *bool) {
 	img.scale += 20
 }
 
+func (img *imageInfo) get() image.Image {
+	if img.scale == 100 {
+		return img.Image
+	}
+	width := uint(float64(img.scale) / 100.0 * float64(img.Bounds().Dx()))
+	height := uint(float64(img.scale) / 100.0 * float64(img.Bounds().Dy()))
+	return resize.Resize(width, height, img.Image, resize.MitchellNetravali)
+}
+
 func min(i, j int) int {
 	if i < j {
 		return i

go.mod

@@ -3,9 +3,7 @@ module github.com/astrogo/fitsio
 go 1.12
 
 require (
-	github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802 // indirect
-	golang.org/x/exp v0.0.0-20180907224206-e88728d35e99
-	golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81 // indirect
-	golang.org/x/mobile v0.0.0-20180918110915-f9c332960c2a
-	golang.org/x/sys v0.0.0-20180918153733-ee1b12c67af4 // indirect
+	github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646
+	golang.org/x/exp v0.0.0-20191030013958-a1ab85dbe136
+	golang.org/x/mobile v0.0.0-20191031020345-0945064e013a
 )

go.sum

@@ -1,10 +1,36 @@
+dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9 h1:VpgP7xuJadIUuKccphEpTJnWhS2jkQyMt6Y7pJCD7fY=
+dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802 h1:1BDTz0u9nC3//pOCMdNH+CiXJVYJh5UQNCOBG7jbELc=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
-golang.org/x/exp v0.0.0-20180907224206-e88728d35e99 h1:7IN8+ZMp04l/19EF+wsr7NM1jyvcadKINimAtWRyQk8=
-golang.org/x/exp v0.0.0-20180907224206-e88728d35e99/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
-golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81 h1:00VmoueYNlNz/aHIilyyQz/MHSqGoWJzpFv/HW8xpzI=
-golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81/go.mod h1:ux5Hcp/YLpHSI86hEcLt0YII63i6oz57MZXIpbrjZUs=
-golang.org/x/mobile v0.0.0-20180918110915-f9c332960c2a h1:g1yx1SSoLJs9YRT5kH1NQo7ioglgoKzoOXPKXU27+fU=
-golang.org/x/mobile v0.0.0-20180918110915-f9c332960c2a/go.mod h1:z+o9i4GpDbdi3rU15maQ/Ox0txvL9dWGYEHz965HBQE=
-golang.org/x/sys v0.0.0-20180918153733-ee1b12c67af4 h1:h8ij2QOL81JqJ/Vi5Ru+hl4a1yct8+XDGrgBhG0XbuE=
-golang.org/x/sys v0.0.0-20180918153733-ee1b12c67af4/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1 h1:QbL/5oDUmRBzO9/Z7Seo6zf912W/a6Sr4Eu0G/3Jho0=
+github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
+github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646 h1:zYyBkD/k9seD2A7fsi6Oo2LfFZAehjjQMERAvZLEDnQ=
+github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646/go.mod h1:jpp1/29i3P1S/RLdc7JQKbRpFeM1dOBd8T9ki5s+AY8=
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