fix html to png

canvas.go

@@ -0,0 +1,141 @@
+package libgofunc
+
+import (
+	"strconv"
+	"strings"
+
+	"github.com/fogleman/gg"
+	"golang.org/x/image/font"
+	"golang.org/x/net/html"
+)
+
+// -------------------- STYLE --------------------
+type Style struct {
+	PaddingLeft   float64
+	PaddingRight  float64
+	PaddingTop    float64
+	PaddingBottom float64
+	FontSize      float64
+	Width         float64
+	Height        float64
+	TextAlign     string
+	VerticalAlign string
+	Border        float64
+}
+
+func parseStyle(styleStr string) Style {
+	style := Style{
+		FontSize:      16,
+		TextAlign:     "left",
+		VerticalAlign: "top",
+	}
+
+	parts := strings.Split(styleStr, ";")
+	for _, p := range parts {
+		kv := strings.SplitN(strings.TrimSpace(p), ":", 2)
+		if len(kv) != 2 {
+			continue
+		}
+		key := strings.TrimSpace(kv[0])
+		val := strings.TrimSpace(kv[1])
+
+		switch key {
+		case "padding":
+			v := parsePx(val)
+			style.PaddingLeft, style.PaddingRight, style.PaddingTop, style.PaddingBottom = v, v, v, v
+		case "padding-left":
+			v := parsePx(val)
+			style.PaddingLeft = v
+		case "padding-right":
+			v := parsePx(val)
+			style.PaddingRight = v
+		case "padding-top":
+			v := parsePx(val)
+			style.PaddingTop = v
+		case "padding-bottom":
+			v := parsePx(val)
+			style.PaddingBottom = v
+		case "font-size":
+			style.FontSize = parsePx(val)
+		case "width":
+			style.Width = parsePx(val)
+		case "height":
+			style.Height = parsePx(val)
+		case "text-align":
+			style.TextAlign = val
+		case "vertical-align":
+			style.VerticalAlign = val
+		case "border":
+			style.Border = parsePx(val)
+		}
+	}
+	return style
+}
+
+func parsePx(v string) float64 {
+	v = strings.ReplaceAll(v, "px", "")
+	f, _ := strconv.ParseFloat(v, 64)
+	return f
+}
+
+// -------------------- NODE --------------------
+type Node struct {
+	Tag      string
+	Text     string
+	Attr     map[string]string
+	Style    Style
+	Children []*Node
+}
+
+func (n Node) getSrc() string {
+	for k, v := range n.Attr {
+		if k == "src" {
+			return v
+		}
+	}
+	return ""
+}
+
+func (n Node) getHeight() int {
+	return int(n.Style.Height)
+}
+
+func BuildTree(n *html.Node, canvasWidth int, dc *gg.Context, face *font.Face) (*Node, int) {
+	if n.Type != html.ElementNode {
+		return nil, 0
+	}
+
+	text := ""
+	if n.Data == "h1" || n.Data == "h2" || n.Data == "h3" ||
+		n.Data == "p" || n.Data == "td" || n.Data == "th" ||
+		n.Type == html.TextNode {
+		text = getText(n)
+	}
+
+	node := &Node{
+		Tag:  n.Data,
+		Text: text,
+		Attr: map[string]string{},
+	}
+
+	for _, a := range n.Attr {
+		node.Attr[a.Key] = a.Val
+	}
+
+	if s, ok := node.Attr["style"]; ok {
+		node.Style = parseStyle(s)
+	}
+	xPadding := node.Style.PaddingLeft + node.Style.PaddingRight
+	yPadding := node.Style.PaddingTop + node.Style.PaddingBottom
+	fontSize := node.Style.FontSize
+	h := nodeHeight(n, dc, canvasWidth, int(xPadding), int(yPadding),
+		face, fontSize, node.getHeight())
+	for c := n.FirstChild; c != nil; c = c.NextSibling {
+		child, ch := BuildTree(c, canvasWidth, dc, face)
+		if child != nil {
+			node.Children = append(node.Children, child)
+		}
+		h += ch
+	}
+	return node, h
+}