Bad rendering

[pebbe]

Rendering of this graph is all wrong:

strict graph gr {
 
    ranksep=".4"
    nodesep=.05
 
    margin=.05;
    outputMode="edgesfirst";
    node [shape=box, height=0, width=0, style=filled, fontsize=12, color="#ffc0c0", fontname="Helvetica"];
 
    n0 [label="top"];
    n1 [label="smain", style=bold, color="#ff0000"];
    n3 [label="np", style=bold, color="#ff0000"];
    n6 [label="ppart", style=bold, color="#ff0000"];
 
    node [fontname="Helvetica-Oblique", color="#c0c0ff"];
 
    n2 [label="werd"];
    n4 [label="groot", style=bold, color="#0000ff"];
    n5 [label="alarm", style=bold, color="#0000ff"];
    n7 [label="Wel"];
    n8 [label="meteen"];
    n10 [label="geslagen"];
 
    {rank=same; edge[style=invis]; n7 -- n2 -- n8 -- n4 -- n5 -- n10}
 
    edge [sametail=true, samehead=true, color="#d3d3d3", fontname="Helvetica", fontsize=10];
 
    n0 -- n1 [label=" --  "];
    n1 -- n2 [label=" hd  "];
    n1 -- n3 [label=" su  ", color="#000000"];
    n1 -- n6 [label=" vc  "];
    n3 -- n4 [label=" mod  ", color="#000000"];
    n3 -- n5 [label=" hd  ", color="#000000"];
    n6 -- n7 [label=" mod  "];
    n6 -- n8 [label=" mod  "];
    n6 -- n3 [label=" svp  ", color="#000000"];
    n6 -- n10 [label=" hd  "];
 
}

How it should look (rendered with the dot program):

How it looks:

[marcelom97]

Looks to be working fine in this example in all 4 formats.

package main

import (
	"context"
	"fmt"
	"log"
	"os"

	"github.com/goccy/go-graphviz"
)

func main() {
	ctx := context.Background()
	gv, err := graphviz.ParseBytes([]byte(`
 strict graph gr {

     ranksep=".4"
     nodesep=.05

     margin=.05;
     outputMode="edgesfirst";
     node [shape=box, height=0, width=0, style=filled, fontsize=12, color="#ffc0c0", fontname="Helvetica"];

     n0 [label="top"];
     n1 [label="smain", style=bold, color="#ff0000"];
     n3 [label="np", style=bold, color="#ff0000"];
     n6 [label="ppart", style=bold, color="#ff0000"];

     node [fontname="Helvetica-Oblique", color="#c0c0ff"];

     n2 [label="werd"];
     n4 [label="groot", style=bold, color="#0000ff"];
     n5 [label="alarm", style=bold, color="#0000ff"];
     n7 [label="Wel"];
     n8 [label="meteen"];
     n10 [label="geslagen"];

     {rank=same; edge[style=invis]; n7 -- n2 -- n8 -- n4 -- n5 -- n10}

     edge [sametail=true, samehead=true, color="#d3d3d3", fontname="Helvetica", fontsize=10];

     n0 -- n1 [label=" --  "];
     n1 -- n2 [label=" hd  "];
     n1 -- n3 [label=" su  ", color="#000000"];
     n1 -- n6 [label=" vc  "];
     n3 -- n4 [label=" mod  ", color="#000000"];
     n3 -- n5 [label=" hd  ", color="#000000"];
     n6 -- n7 [label=" mod  "];
     n6 -- n8 [label=" mod  "];
     n6 -- n3 [label=" svp  ", color="#000000"];
     n6 -- n10 [label=" hd  "];
 }`))
	if err != nil {
		log.Fatal("failed to parse graphviz: ", err)
	}

	g, err := graphviz.New(ctx)
	if err != nil {
		log.Fatal("failed to create graphviz: ", err)
	}

	formats := []graphviz.Format{graphviz.PNG, graphviz.SVG, graphviz.JPG, graphviz.XDOT}
	for _, format := range formats {
		f, err := os.Create(fmt.Sprintf("example.%s", format))
		if err != nil {
			log.Fatal("failed to create file: ", err)
		}
		defer f.Close()

		if err := g.Render(ctx, gv, format, f); err != nil {
			// don't exit here, just log the error
			fmt.Printf("failed to render graph to %s: %v\n", format, err)
		}
	}
}

[pebbe]

Running this code I get what you see below. Only the svg version (top right) looks identical to the original (top left). Is it something platform dependant? I am using Go version go1.23.2 on linux/amd64.

[pebbe]

Or is it a library version thing? This is my go.mod for this program:

require github.com/goccy/go-graphviz v0.2.9
 
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
        github.com/tetratelabs/wazero v1.8.1 // indirect
        golang.org/x/image v0.21.0 // indirect
        golang.org/x/text v0.19.0 // indirect
)

[marcelom97]

I ran it on go1.23.2 darwin/arm64

Maybe try to run it in docker on a different platform

[WolvenSpirit]

Same bug with rendering edges happens on my platform also (which is actually Github codespace)

$ uname -ai
Linux codespaces-51c77b 6.5.0-1025-azure #26~22.04.1-Ubuntu SMP Thu Jul 11 22:33:04 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

go version go1.23.1 linux/amd64

From go.mod

require github.com/goccy/go-graphviz v0.2.9

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
	github.com/tetratelabs/wazero v1.8.1 // indirect
	golang.org/x/image v0.22.0 // indirect
	golang.org/x/text v0.20.0 // indirect
)

Reproducing it in codespace would be trivial as it happens out of the box.

[goccy]

It’s likely an issue with the feature you are using. Does the rendering break with a simpler example as well ? If not, please provide a minimal sample.

[WolvenSpirit]

An example, I skipped a lot of things to get a really slim code sample. Note: The codespace dev env is as provided by Github nothing was installed besides this library via go get ....

package main

import (
	"context"

	gv "github.com/goccy/go-graphviz"
)

func main() {
	ctx := context.Background()
	g, _ := gv.New(ctx)
	graph, _ := g.Graph()
	a, _ := graph.CreateNodeByName("a")
	b, _ := graph.CreateNodeByName("b")
	c, _ := graph.CreateNodeByName("c")
	d, _ := graph.CreateNodeByName("d")
	e, _ := graph.CreateNodeByName("e")
	f, _ := graph.CreateNodeByName("f")
	a.Root().CreateEdgeByName("a-b", a, b)
	a.Root().CreateEdgeByName("a-c", a, c)
	b.Root().CreateEdgeByName("b-c", b, c)
	a.Root().CreateEdgeByName("a-d", a, d)
	d.Root().CreateEdgeByName("d-e", d, e)
	e.Root().CreateEdgeByName("e-f", e, f)
	g.RenderFilename(ctx, graph, "png", "sample.png")
}

Output While the svg code would seem to render properly when doing

// instead of RenderFilename
buff := new(bytes.Buffer)
g.Render(ctx, graph, "svg", buff)
ioutil.WriteFile("sample.svg", buff.Bytes(), fs.ModePerm)

Output

So probably this is either specific to RenderFilename or rendering png/jpg specifically.

[lubronzhan]

I'm also creating a PNG image. Running on mac, golang 1.22.9. I have much more components so the rendering effect is much much worst. For example, small piece of it

I tried several go-graphvzi versions, it happens starting on v0.2.1, the graph is correct with v0.2.0, so it's highly likely due to this PR https://github.com/goccy/go-graphviz/pull/92 according to https://github.com/goccy/go-graphviz/compare/v0.2.0...v0.2.1 Snipped of image using 0.2.0:

This PR just fixes https://github.com/goccy/go-graphviz/issues/24, the images wasn't render correctly previously before 0.2.1, this PR fixes it. So by default looks like the edge use that chubby style. But if I tried set the edge style it doesn't work

edge.SetStyle(cgraph.SolidEdgeStyle)

Not sure where does the filled value is set, we do set Node's style as filled. Maybe the node's fill will also impact the Edge?

[little-nil]

I encountered the same issue. While exporting the DOT file to a PNG image locally on my Mac mini M4 works fine and displays correctly, when deployed to the production environment (Linux x86 Docker), the image generated by the API call shows display issues, just like the user mentioned above.

After downgrading to version v0.2.0 in the production environment, the edges now display correctly. However, the nodes appear without borders. Still, compared to v0.2.9, at least it's usable.