Support image (#96)

* support image rendering

* support fixedsize attr

* add logo.png

.gitignore

@@ -4,3 +4,4 @@
 *.jpg
 .DS_Store
 bin
+internal/wasm/build/graphviz

cdt/link.go

@@ -0,0 +1,12 @@
+package cdt
+
+import (
+	"github.com/goccy/go-graphviz/internal/wasm"
+)
+
+func toLinkWasm(v *Link) *wasm.DictLink {
+	if v == nil {
+		return nil
+	}
+	return v.wasm
+}

cgraph/attribute.go

@@ -698,6 +698,10 @@ func (n *Node) SetFillColor(v string) *Node {
 	return n
 }
 
+func (n *Node) FixedSize() bool {
+	return n.GetStr(string(fixedSizeAttr)) == toBoolString(true)
+}
+
 // SetFixedSize
 // If false, the size of a node is determined by smallest width and height needed to contain its label and image,
 // if any, with a margin specified by the margin attribute.
@@ -1045,14 +1049,32 @@ func (n *Node) SetImagePos(v ImagePos) *Node {
 	return n
 }
 
+type ImageScale string
+
+const (
+	ImageScaleDefault ImageScale = "false"
+	ImageScaleTrue    ImageScale = "true"
+	ImageScaleWidth   ImageScale = "width"
+	ImageScaleHeight  ImageScale = "height"
+	ImageScaleBoth    ImageScale = "both"
+)
+
+func (n *Node) ImageScale() ImageScale {
+	v := n.GetStr(string(imageScaleAttr))
+	if v == "" {
+		return ImageScaleDefault
+	}
+	return ImageScale(v)
+}
+
 // SetImageScale
 // Attribute controlling how an image fills its containing node. In general, the image is given its natural size, (cf. dpi), and the node size is made large enough to contain its image, its label, its margin, and its peripheries. Its width and height will also be at least as large as its minimum width and height. If, however, fixedsize=true, the width and height attributes specify the exact size of the node.
 // During rendering, in the default case (imagescale=false), the image retains its natural size. If imagescale=true, the image is uniformly scaled (i.e., its aspect ratio is preserved) to fit inside the node. At least one dimension of the image will be as large as possible given the size of the node. When imagescale=width, the width of the image is scaled to fill the node width. The corresponding property holds when imagescale=height. When imagescale=both, both the height and the width are scaled separately to fill the node.
 //
 // In all cases, if a dimension of the image is larger than the corresponding dimension of the node, that dimension of the image is scaled down to fit the node. As with the case of expansion, if imagescale=true, width and height are scaled uniformly.
 // https://graphviz.gitlab.io/_pages/doc/info/attrs.html#a:imagescale
-func (n *Node) SetImageScale(v bool) *Node {
-	n.SafeSet(string(imageScaleAttr), toBoolString(v), falseStr)
+func (n *Node) SetImageScale(v ImageScale) *Node {
+	n.SafeSet(string(imageScaleAttr), string(v), string(ImageScaleDefault))
 	return n
 }
 
@@ -1072,7 +1094,7 @@ func (g *Graph) SetInputScale(v float64) *Graph {
 }
 
 // Label returns label attribute.
-func (g *Graph) Label() (string, error) {
+func (g *Graph) Label() string {
 	return g.GetStr(string(labelAttr))
 }
 
@@ -1090,7 +1112,7 @@ func (g *Graph) SetLabel(v string) *Graph {
 }
 
 // Label returns label attribute.
-func (n *Node) Label() (string, error) {
+func (n *Node) Label() string {
 	return n.GetStr(string(labelAttr))
 }
 
@@ -1108,7 +1130,7 @@ func (n *Node) SetLabel(v string) *Node {
 }
 
 // Label returns label attribute.
-func (e *Edge) Label() (string, error) {
+func (e *Edge) Label() string {
 	return e.GetStr(string(labelAttr))
 }
 

cgraph/cgraph.go

@@ -298,7 +298,11 @@ func ParseBytes(bytes []byte) (*Graph, error) {
 	if graph == nil {
 		return nil, lastError()
 	}
-	return toGraph(graph), nil
+	g := toGraph(graph)
+	if err := setupNodeLabelIfEmpty(g); err != nil {
+		return nil, err
+	}
+	return g, nil
 }
 
 func ParseFile(path string) (*Graph, error) {
@@ -317,7 +321,44 @@ func Open(name string, desc *Desc, disc *Disc) (*Graph, error) {
 	if graph == nil {
 		return nil, lastError()
 	}
-	return toGraph(graph), nil
+	g := toGraph(graph)
+	if err := setupNodeLabelIfEmpty(g); err != nil {
+		return nil, err
+	}
+	return g, nil
+}
+
+func setupNodeLabelIfEmpty(g *Graph) error {
+	n, err := g.FirstNode()
+	if err != nil {
+		return err
+	}
+	if n == nil {
+		return nil
+	}
+	if err := setLabelIfEmpty(n); err != nil {
+		return err
+	}
+	for {
+		n, err = g.NextNode(n)
+		if err != nil {
+			return err
+		}
+		if n == nil {
+			break
+		}
+		if err := setLabelIfEmpty(n); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func setLabelIfEmpty(n *Node) error {
+	if n.Label() == "" {
+		n.SetLabel("\\N")
+	}
+	return nil
 }
 
 type ObjectTag int
@@ -777,8 +818,9 @@ func (g *Graph) DeleteRecord(name string) error {
 	return toError(res)
 }
 
-func (g *Graph) GetStr(name string) (string, error) {
-	return wasm.GetStr(context.Background(), g.wasm, name)
+func (g *Graph) GetStr(name string) string {
+	v, _ := wasm.GetStr(context.Background(), g.wasm, name)
+	return v
 }
 
 func (g *Graph) SymbolName(sym *Symbol) (string, error) {
@@ -1236,8 +1278,9 @@ func (n *Node) DeleteRecord(name string) error {
 	return toError(res)
 }
 
-func (n *Node) GetStr(name string) (string, error) {
-	return wasm.GetStr(context.Background(), n.wasm, name)
+func (n *Node) GetStr(name string) string {
+	v, _ := wasm.GetStr(context.Background(), n.wasm, name)
+	return v
 }
 
 func (n *Node) SymbolName(sym *Symbol) (string, error) {
@@ -1319,8 +1362,9 @@ func (e *Edge) DeleteRecord(name string) error {
 	return toError(res)
 }
 
-func (e *Edge) GetStr(name string) (string, error) {
-	return wasm.GetStr(context.Background(), e.wasm, name)
+func (e *Edge) GetStr(name string) string {
+	v, _ := wasm.GetStr(context.Background(), e.wasm, name)
+	return v
 }
 
 func (e *Edge) SymbolName(sym *Symbol) (string, error) {

cmd/dot/go.mod

@@ -11,6 +11,7 @@ require (
 )
 
 require (
+	github.com/disintegration/imaging v1.6.2 // indirect
 	github.com/flopp/go-findfont v0.1.0 // indirect
 	github.com/fogleman/gg v1.3.0 // indirect
 	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect

cmd/dot/go.sum

@@ -1,5 +1,7 @@
 github.com/corona10/goimagehash v1.1.0 h1:teNMX/1e+Wn/AYSbLHX8mj+mF9r60R1kBeqE9MkoYwI=
 github.com/corona10/goimagehash v1.1.0/go.mod h1:VkvE0mLn84L4aF8vCb6mafVajEb6QYMHl2ZJLn0mOGI=
+github.com/disintegration/imaging v1.6.2 h1:w1LecBlG2Lnp8B3jk5zSuNqd7b4DXhcjwek1ei82L+c=
+github.com/disintegration/imaging v1.6.2/go.mod h1:44/5580QXChDfwIclfc/PCwrr44amcmDAg8hxG0Ewe4=
 github.com/flopp/go-findfont v0.1.0 h1:lPn0BymDUtJo+ZkV01VS3661HL6F4qFlkhcJN55u6mU=
 github.com/flopp/go-findfont v0.1.0/go.mod h1:wKKxRDjD024Rh7VMwoU90i6ikQRCr+JTHB5n4Ejkqvw=
 github.com/fogleman/gg v1.3.0 h1:/7zJX8F6AaYQc57WQCyN9cAIz+4bCJGO9B+dyW29am8=
@@ -12,11 +14,13 @@ github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646 h1:zYyBkD/k9seD2A7fsi6
 github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646/go.mod h1:jpp1/29i3P1S/RLdc7JQKbRpFeM1dOBd8T9ki5s+AY8=
 github.com/tetratelabs/wazero v1.8.1 h1:NrcgVbWfkWvVc4UtT4LRLDf91PsOzDzefMdwhLfA550=
 github.com/tetratelabs/wazero v1.8.1/go.mod h1:yAI0XTsMBhREkM/YDAK/zNou3GoiAce1P6+rp/wQhjs=
+golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/image v0.21.0 h1:c5qV36ajHpdj4Qi0GnE0jUc/yuo33OLFaa0d+crTD5s=
 golang.org/x/image v0.21.0/go.mod h1:vUbsLavqK/W303ZroQQVKQ+Af3Yl6Uz1Ppu5J/cLz78=
 golang.org/x/sys v0.26.0 h1:KHjCJyddX0LoSTb3J+vWpupP9p0oznkqVk/IfjymZbo=
 golang.org/x/sys v0.26.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.25.0 h1:WtHI/ltw4NvSUig5KARz9h521QvRC8RmF/cuYqifU24=
 golang.org/x/term v0.25.0/go.mod h1:RPyXicDX+6vLxogjjRxjgD2TKtmAO6NZBsBRfrOLu7M=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.19.0 h1:kTxAhCbGbxhK0IwgSKiMO5awPoDQ0RpfiVYBfK860YM=
 golang.org/x/text v0.19.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=

go.mod

@@ -4,6 +4,7 @@ go 1.22.0
 
 require (
 	github.com/corona10/goimagehash v1.1.0
+	github.com/disintegration/imaging v1.6.2
 	github.com/flopp/go-findfont v0.1.0
 	github.com/fogleman/gg v1.3.0
 	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0

go.sum

@@ -1,5 +1,7 @@
 github.com/corona10/goimagehash v1.1.0 h1:teNMX/1e+Wn/AYSbLHX8mj+mF9r60R1kBeqE9MkoYwI=
 github.com/corona10/goimagehash v1.1.0/go.mod h1:VkvE0mLn84L4aF8vCb6mafVajEb6QYMHl2ZJLn0mOGI=
+github.com/disintegration/imaging v1.6.2 h1:w1LecBlG2Lnp8B3jk5zSuNqd7b4DXhcjwek1ei82L+c=
+github.com/disintegration/imaging v1.6.2/go.mod h1:44/5580QXChDfwIclfc/PCwrr44amcmDAg8hxG0Ewe4=
 github.com/flopp/go-findfont v0.1.0 h1:lPn0BymDUtJo+ZkV01VS3661HL6F4qFlkhcJN55u6mU=
 github.com/flopp/go-findfont v0.1.0/go.mod h1:wKKxRDjD024Rh7VMwoU90i6ikQRCr+JTHB5n4Ejkqvw=
 github.com/fogleman/gg v1.3.0 h1:/7zJX8F6AaYQc57WQCyN9cAIz+4bCJGO9B+dyW29am8=
@@ -10,7 +12,9 @@ github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646 h1:zYyBkD/k9seD2A7fsi6
 github.com/nfnt/resize v0.0.0-20180221191011-83c6a9932646/go.mod h1:jpp1/29i3P1S/RLdc7JQKbRpFeM1dOBd8T9ki5s+AY8=
 github.com/tetratelabs/wazero v1.8.1 h1:NrcgVbWfkWvVc4UtT4LRLDf91PsOzDzefMdwhLfA550=
 github.com/tetratelabs/wazero v1.8.1/go.mod h1:yAI0XTsMBhREkM/YDAK/zNou3GoiAce1P6+rp/wQhjs=
+golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/image v0.21.0 h1:c5qV36ajHpdj4Qi0GnE0jUc/yuo33OLFaa0d+crTD5s=
 golang.org/x/image v0.21.0/go.mod h1:vUbsLavqK/W303ZroQQVKQ+Af3Yl6Uz1Ppu5J/cLz78=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.19.0 h1:kTxAhCbGbxhK0IwgSKiMO5awPoDQ0RpfiVYBfK860YM=
 golang.org/x/text v0.19.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=

graphviz.go

@@ -4,9 +4,11 @@ import (
 	"context"
 	"image"
 	"io"
+	"io/fs"
 
 	"github.com/goccy/go-graphviz/cgraph"
 	"github.com/goccy/go-graphviz/gvc"
+	"github.com/goccy/go-graphviz/internal/wasm"
 )
 
 type Graphviz struct {
@@ -133,3 +135,7 @@ func (g *Graphviz) Graph(option ...GraphOption) (*Graph, error) {
 	}
 	return graph, nil
 }
+
+func SetFileSystem(fs fs.FS) {
+	wasm.SetWasmFileSystem(fs)
+}

graphviz_test.go

@@ -3,7 +3,10 @@ package graphviz_test
 import (
 	"bytes"
 	"context"
+	"embed"
+	"io/fs"
 	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/goccy/go-graphviz"
@@ -160,6 +163,58 @@ func TestParseFile(t *testing.T) {
 	}
 }
 
+//go:embed testdata/logo.png
+var logoFS embed.FS
+
+type imageFS struct{}
+
+func (fs *imageFS) Open(name string) (fs.File, error) {
+	return logoFS.Open(filepath.Join("testdata", name))
+}
+
+func TestImageRender(t *testing.T) {
+	ctx := context.Background()
+	graphviz.SetFileSystem(new(imageFS))
+
+	g, err := graphviz.New(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	graph, err := g.Graph()
+	if err != nil {
+		t.Fatalf("%+v", err)
+	}
+	defer func() {
+		graph.Close()
+		g.Close()
+	}()
+	n, err := graph.CreateNodeByName("n")
+	if err != nil {
+		t.Fatalf("%+v", err)
+	}
+	n.SetLabel("")
+
+	// specify dummy image path.
+	// Normally, a path to `testdata` would be required before `logo.png`,
+	// but we confirm that the image can be loaded by appending the path to `testdata` within the `imageFS` specified by graphviz.SetFileSystem function.
+	// This test is to verify that images can be loaded relative to the specified FileSystem.
+	n.SetImage("logo.png")
+	m, err := graph.CreateNodeByName("m")
+	if err != nil {
+		t.Fatalf("%+v", err)
+	}
+	if _, err := graph.CreateEdgeByName("e", n, m); err != nil {
+		t.Fatalf("%+v", err)
+	}
+	var buf bytes.Buffer
+	if err := g.Render(ctx, graph, "png", &buf); err != nil {
+		t.Fatal(err)
+	}
+	if len(buf.Bytes()) == 0 {
+		t.Fatal("failed to render image")
+	}
+}
+
 func TestNodeDegree(t *testing.T) {
 	type test struct {
 		nodeName            string

gvc/gvc.go

@@ -50,9 +50,6 @@ func (c *Context) Close() error {
 }
 
 func (c *Context) Layout(ctx context.Context, g *cgraph.Graph, engine string) error {
-	if err := c.setupNodeLabelIfEmpty(g); err != nil {
-		return err
-	}
 	res, err := c.gvc.Layout(ctx, toGraphWasm(g), engine)
 	if err != nil {
 		return err
@@ -114,40 +111,6 @@ func (c *Context) FreeClonedContext(ctx context.Context) error {
 	return c.gvc.FreeClonedContext(ctx)
 }
 
-func (c *Context) setupNodeLabelIfEmpty(g *cgraph.Graph) error {
-	n, err := g.FirstNode()
-	if err != nil {
-		return err
-	}
-	if err := c.setLabelIfEmpty(n); err != nil {
-		return err
-	}
-	for {
-		n, err = g.NextNode(n)
-		if err != nil {
-			return err
-		}
-		if n == nil {
-			break
-		}
-		if err := c.setLabelIfEmpty(n); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func (c *Context) setLabelIfEmpty(n *cgraph.Node) error {
-	label, err := n.Label()
-	if err != nil {
-		return err
-	}
-	if label == "" {
-		n.SetLabel("\\N")
-	}
-	return nil
-}
-
 func newPlugins(ctx context.Context, plugins ...Plugin) ([]*wasm.SymList, error) {
 	defaults, err := wasm.DefaultSymList(ctx)
 	if err != nil {
@@ -190,7 +153,7 @@ func newPlugins(ctx context.Context, plugins ...Plugin) ([]*wasm.SymList, error)
 	if err != nil {
 		return nil, err
 	}
-	return append(defaults, sym, symTerm), nil
+	return append(append([]*wasm.SymList{sym}, defaults...), symTerm), nil
 }
 
 func toError(result int) error {