ref: d5a4d882a221f32721bc9608d14bfbad0583c50b
dir: /style/stylesheets.go/
package style
import (
"9fans.net/go/draw"
"bytes"
"fmt"
"github.com/andybalholm/cascadia"
"github.com/chris-ramon/douceur/css"
"github.com/chris-ramon/douceur/parser"
"github.com/mjl-/duit"
"github.com/psilva261/opossum/logger"
"golang.org/x/image/colornames"
"golang.org/x/net/html"
"image"
"math"
"os/exec"
"regexp"
"runtime"
"strconv"
"strings"
)
var fontCache = make(map[string]*draw.Font)
var dui *duit.DUI
var availableFontNames []string
var rMinWidth = regexp.MustCompile(`min-width: (\d+)(px|em|rem)`)
var rMaxWidth = regexp.MustCompile(`max-width: (\d+)(px|em|rem)`)
const FontBaseSize = 11.0
var WindowWidth = 1280
var WindowHeight = 1080
const AddOnCSS = `
/* https://developer.mozilla.org/en-US/docs/Web/HTML/Inline_elements */
a, abbr, acronym, audio, b, bdi, bdo, big, br, button, canvas, cite, code, data, datalist, del, dfn, em, embed, i, iframe, img, input, ins, kbd, label, map, mark, meter, noscript, object, output, picture, progress, q, ruby, s, samp, script, select, slot, small, span, strong, sub, sup, svg, template, textarea, time, u, tt, var, video, wbr {
display: inline;
}
/* non-HTML5 elements: https://www.w3schools.com/tags/ref_byfunc.asp */
font, strike, tt {
display: inline;
}
button, textarea, input, select {
display: inline-block;
}
/* https://developer.mozilla.org/en-US/docs/Web/HTML/Block-level_elements */
address, article, aside, blockquote, details, dialog, dd, div, dl, dt, fieldset, figcaption, figure, footer, form, h1, h2, h3, h4, h5, h6, header, hgroup, hr, li, main, nav, ol, p, pre, section, table, ul {
display: block;
}
a[href] {
color: blue;
margin-right: 2px;
}
`
func Init(d *duit.DUI) {
dui = d
initFontserver()
}
func Hrefs(doc *html.Node) (hrefs []string) {
hrefs = make([]string, 0, 3)
var f func(n *html.Node)
f = func(n *html.Node) {
if n.Type == html.ElementNode && n.Data == "link" {
isStylesheet := false
isPrint := false
href := ""
for _, a := range n.Attr {
switch strings.ToLower(a.Key) {
case "rel":
if a.Val == "stylesheet" {
isStylesheet = true
}
case "href":
href = a.Val
case "media":
isPrint = a.Val == "print"
}
}
if isStylesheet && !isPrint {
hrefs = append(hrefs, href)
}
}
for c := n.FirstChild; c != nil; c = c.NextSibling {
f(c)
}
}
f(doc)
return
}
func MergeNodeMaps(m, addOn map[*html.Node]Map) {
for n, mp := range addOn {
// "zero" valued Map if it doesn't exist yet
initial := m[n]
m[n] = initial.ApplyChildStyle(mp, true)
}
}
func FetchNodeMap(doc *html.Node, cssText string, windowWidth int) (m map[*html.Node]Map, err error) {
mr, rv, err := FetchNodeRules(doc, cssText, windowWidth)
if err != nil {
return nil, fmt.Errorf("fetch rules: %w", err)
}
m = make(map[*html.Node]Map)
for n, rs := range mr {
ds := make(map[string]css.Declaration)
for _, r := range rs {
for _, d := range r.Declarations {
if exist, ok := ds[d.Property]; ok && smaller(*d, exist) {
continue
}
if strings.HasPrefix(d.Value, "var(") {
v := strings.TrimPrefix(d.Value, "var(")
v = strings.TrimSuffix(v, ")")
if vv, ok := rv[v]; ok {
d.Value = vv
}
}
ds[d.Property] = *d
}
}
m[n] = Map{Declarations: ds}
}
return
}
func smaller(d, dd css.Declaration) bool {
return dd.Important
}
func compile(v string) (cs cascadia.Selector, err error) {
l := strings.Split(v, " ")
for _, s := range l {
s = strings.TrimSpace(s)
if strings.HasSuffix(s, ":") {
// TODO: selectors like .selector: would crash otherwise
err = fmt.Errorf("unsupported selector: %v", s)
return
}
}
return cascadia.Compile(v)
}
func FetchNodeRules(doc *html.Node, cssText string, windowWidth int) (m map[*html.Node][]*css.Rule, rVars map[string]string, err error) {
m = make(map[*html.Node][]*css.Rule)
rVars = make(map[string]string)
s, err := parser.Parse(cssText)
if err != nil {
return nil, nil, fmt.Errorf("douceur parse: %w", err)
}
processRule := func(m map[*html.Node][]*css.Rule, r *css.Rule) (err error) {
for _, sel := range r.Selectors {
if sel.Value == ":root" {
for _, d := range r.Declarations {
rVars[d.Property] = d.Value
}
}
cs, err := compile(sel.Value)
if err != nil {
log.Printf("cssSel compile %v: %v", sel.Value, err)
continue
}
for _, el := range cascadia.QueryAll(doc, cs) {
existing, ok := m[el]
if !ok {
existing = make([]*css.Rule, 0, 3)
}
existing = append(existing, r)
m[el] = existing
}
}
return
}
for _, r := range s.Rules {
if err := processRule(m, r); err != nil {
return nil, nil, fmt.Errorf("process rule: %w", err)
}
// for media queries
if strings.Contains(r.Prelude, "print") && !strings.Contains(r.Prelude, "screen") {
continue
}
if rMaxWidth.MatchString(r.Prelude) {
m := rMaxWidth.FindStringSubmatch(r.Prelude)
l := m[1] + m[2]
maxWidth, _, err := length(nil, l)
if err != nil {
return nil, nil, fmt.Errorf("atoi: %w", err)
}
if float64(windowWidth) > maxWidth {
continue
}
}
if rMinWidth.MatchString(r.Prelude) {
m := rMinWidth.FindStringSubmatch(r.Prelude)
l := m[1] + m[2]
minWidth, _, err := length(nil, l)
if err != nil {
return nil, nil, fmt.Errorf("atoi: %w", err)
}
if float64(windowWidth) < minWidth {
continue
}
}
for _, rr := range r.Rules {
if err := processRule(m, rr); err != nil {
return nil, nil, fmt.Errorf("process embedded rule: %w", err)
}
}
}
return
}
type DomTree interface {
Rect() image.Rectangle
Parent() (p DomTree, ok bool)
Style() Map
}
type Map struct {
Declarations map[string]css.Declaration
DomTree `json:"-"`
}
func NewMap(n *html.Node) Map {
s := Map{
Declarations: make(map[string]css.Declaration),
}
for _, a := range n.Attr {
if a.Key == "style" {
v := strings.TrimSpace(a.Val)
if !strings.HasSuffix(v, ";") {
v += ";"
}
decls, err := parser.ParseDeclarations(v)
if err != nil {
log.Printf("could not parse '%v'", a.Val)
break
}
for _, d := range decls {
s.Declarations[d.Property] = *d
}
} else if a.Key == "height" || a.Key == "width" {
v := a.Val
if !strings.HasSuffix(v, "%") && !strings.HasSuffix(v, "px") {
v += "px"
}
s.Declarations[a.Key] = css.Declaration{
Property: a.Key,
Value: v,
}
} else if a.Key == "bgcolor" {
s.Declarations["background-color"] = css.Declaration{
Property: "background-color",
Value: a.Val,
}
}
}
return s
}
func (cs Map) ApplyChildStyle(ccs Map, copyAll bool) (res Map) {
res.Declarations = make(map[string]css.Declaration)
for k, v := range cs.Declarations {
switch k {
// https://www.w3.org/TR/CSS21/propidx.html
case "azimuth", "border-collapse", "border-spacing", "caption-side", "color", "cursor", "direction", "elevation", "empty-cells", "font-family", "font-size", "font-style", "font-variant", "font-weight", "font", "letter-spacing", "line-height", "list-style-image", "list-style-position", "list-style-type", "list-style", "orphans", "pitch-range", "pitch", "quotes", "richness", "speak-header", "speak-numeral", "speak-punctuation", "speak", "speech-rate", "stress", "text-align", "text-indent", "text-transform", "visibility", "voice-family", "volume", "white-space", "widows", "word-spacing":
default:
if !copyAll {
continue
}
}
res.Declarations[k] = v
}
// overwrite with higher prio child props
for k, v := range ccs.Declarations {
if v.Value == "inherit" {
continue
}
res.Declarations[k] = v
}
return
}
func (cs Map) Font() *draw.Font {
fn, ok := cs.FontFilename()
if !ok || dui == nil {
return nil
}
if runtime.GOOS == "plan9" && dui.Display.HiDPI() {
// TODO: proper hidpi handling
return dui.Font(nil)
}
font, ok := fontCache[fn]
if ok {
return font
}
log.Infof("call dui.Display.OpenFont(%v)", fn)
font, err := dui.Display.OpenFont(fn)
if err != nil {
log.Printf("%v is not avail", fn)
return nil
}
fontCache[fn] = font
return font
}
func (cs Map) preferedFontName(preferences []string) string {
avails := availableFontNames
if len(avails) == 0 {
return preferences[0]
}
for len(preferences) > 0 {
var pref string
pref, preferences = preferences[0], preferences[1:]
for _, avail := range avails {
if pref == strings.TrimSuffix(avail, "/") {
return avail
}
}
}
return avails[0]
}
func matchClosestFontSize(desired float64, available []int) (closest int) {
for _, a := range available {
if closest == 0 || math.Abs(float64(a)-desired) < math.Abs(float64(closest)-desired) {
closest = a
}
}
return
}
func (cs Map) FontSize() float64 {
fs, ok := cs.Declarations["font-size"]
if !ok || fs.Value == "" {
return FontBaseSize
}
if len(fs.Value) <= 2 {
log.Printf("error parsing font size %v", fs.Value)
return FontBaseSize
}
numStr := fs.Value[0 : len(fs.Value)-2]
f, err := strconv.ParseFloat(numStr, 64)
if err != nil {
log.Printf("error parsing font size %v", fs.Value)
return FontBaseSize
}
if strings.HasSuffix(fs.Value, "em") {
f *= FontBaseSize
}
return f
}
// FontHeight in lowDPI pixels.
func (cs Map) FontHeight() float64 {
return float64(cs.Font().Height) / float64(dui.Scale(1))
}
func (cs Map) Color() draw.Color {
if d, ok := cs.Declarations["color"]; ok {
if h, ok := colorHex(d.Value); ok {
c := draw.Color(h)
return c
}
}
return draw.Black
}
func colorHex(propVal string) (c draw.Color, ok bool) {
var r, g, b uint32
var x uint32
if strings.HasPrefix(propVal, "rgb") {
val := propVal[3:]
val = strings.TrimPrefix(val, "a")
val = strings.TrimPrefix(val, "(")
val = strings.TrimSuffix(val, ")")
vals := strings.Split(val, ",")
if len(vals) < 3 {
log.Errorf("vals=%+v", vals)
return
}
rr, err := strconv.ParseInt(vals[0], 10, 32)
if err != nil {
goto default_value
}
gg, err := strconv.ParseInt(vals[1], 10, 32)
if err != nil {
goto default_value
}
bb, err := strconv.ParseInt(vals[2], 10, 32)
if err != nil {
goto default_value
}
r = uint32(rr) * 256
g = uint32(gg) * 256
b = uint32(bb) * 256
} else if strings.HasPrefix(propVal, "#") {
hexColor := propVal[1:]
if len(hexColor) == 3 {
rr, err := strconv.ParseInt(hexColor[0:1], 16, 32)
if err != nil {
goto default_value
}
gg, err := strconv.ParseInt(hexColor[1:2], 16, 32)
if err != nil {
goto default_value
}
bb, err := strconv.ParseInt(hexColor[2:3], 16, 32)
if err != nil {
goto default_value
}
r = uint32(rr) * 256 * 0x11
g = uint32(gg) * 256 * 0x11
b = uint32(bb) * 256 * 0x11
} else if len(hexColor) == 6 {
rr, err := strconv.ParseInt(hexColor[0:2], 16, 32)
if err != nil {
goto default_value
}
gg, err := strconv.ParseInt(hexColor[2:4], 16, 32)
if err != nil {
goto default_value
}
bb, err := strconv.ParseInt(hexColor[4:6], 16, 32)
if err != nil {
goto default_value
}
r = uint32(rr) * 256
g = uint32(gg) * 256
b = uint32(bb) * 256
} else {
goto default_value
}
} else if propVal == "inherit" {
// TODO: handle properly
goto default_value
} else {
colorRGBA, ok := colornames.Map[propVal]
if !ok {
goto default_value
}
r, g, b, _ = colorRGBA.RGBA()
}
x = (r / 256) << 24
x = x | ((g / 256) << 16)
x = x | ((b / 256) << 8)
x = x | 0x000000ff
return draw.Color(uint32(x)), true
default_value:
log.Printf("could not interpret %v", propVal)
return 0, false
}
func (cs Map) IsInline() bool {
propVal, ok := cs.Declarations["float"]
if ok && propVal.Value == "left" {
return true
}
propVal, ok = cs.Declarations["display"]
if ok {
return propVal.Value == "inline" ||
propVal.Value == "inline-block"
}
return false
}
func (cs Map) IsDisplayNone() bool {
propVal, ok := cs.Declarations["display"]
if ok && propVal.Value == "none" {
return true
}
/*propVal, ok = cs.Declarations["position"]
if ok && propVal.Value == "fixed" {
return true
}*/
propVal, ok = cs.Declarations["clip"]
if ok && strings.ReplaceAll(propVal.Value, " ", "") == "rect(1px,1px,1px,1px)" {
return true
}
propVal, ok = cs.Declarations["width"]
if ok && propVal.Value == "1px" {
propVal, ok = cs.Declarations["height"]
if ok && propVal.Value == "1px" {
return true
}
}
return false
}
func (cs Map) IsFlex() bool {
propVal, ok := cs.Declarations["display"]
if ok {
return propVal.Value == "flex"
}
return false
}
func (cs Map) IsFlexDirectionRow() bool {
propVal, ok := cs.Declarations["flex-direction"]
if ok {
switch propVal.Value {
case "row":
return true
case "column":
return false
}
}
return true // TODO: be more specific
}
// tlbr parses 4-tuple of top-right-bottom-left like in margin,
// margin-top, ...-right, ...-bottom, ...-left.
func (cs *Map) Tlbr(key string) (s duit.Space, err error) {
if all, ok := cs.Declarations[key]; ok {
parts := strings.Split(all.Value, " ")
nums := make([]int, len(parts))
for i, p := range parts {
if f, _, err := length(cs, p); err == nil {
nums[i] = int(f)
} else {
return s, fmt.Errorf("length: %w", err)
}
}
s.Top = nums[0]
s.Right = s.Top
s.Bottom = s.Top
s.Left = s.Top
if len(nums) >= 2 {
s.Right = nums[1]
s.Left = s.Right
}
if len(nums) >= 3 {
s.Bottom = nums[2]
}
if len(nums) == 4 {
s.Left = nums[3]
}
}
if t, err := cs.CssPx(key + "-top"); err == nil {
s.Top = t
}
if r, err := cs.CssPx(key + "-right"); err == nil {
s.Right = r
}
if b, err := cs.CssPx(key + "-bottom"); err == nil {
s.Bottom = b
}
if l, err := cs.CssPx(key + "-left"); err == nil {
s.Left = l
}
// Limit very rudimentary relative unit calculation
if s.Top > 100 {
s.Top = 0
}
if s.Bottom > 100 {
s.Bottom = 0
}
return
}
var reBcInput = regexp.MustCompile(`^[0-9\+\*\-\/\(\)\\.\s]+$`)
func calc(cs *Map, l string) (f float64, unit string, err error) {
if !strings.HasPrefix(l, "calc(") && !strings.HasSuffix(l, ")") {
return 0, "", fmt.Errorf("wrong format")
}
l = strings.TrimPrefix(l, "calc(")
l = strings.TrimSuffix(l, ")")
if len(l) > 50 {
return 0, "", fmt.Errorf("parse expression: %v", l)
}
l = strings.ReplaceAll(l, "px", "")
for _, u := range []string{"rem", "em", "%", "vw", "vh"} {
if !strings.Contains(l, u) {
continue
}
r, _, err := length(cs, "1"+u)
if err != nil {
return 0, "", fmt.Errorf("u %v: %v", u, err)
}
l = strings.ReplaceAll(l, u, fmt.Sprintf("*%v", r))
}
if !reBcInput.MatchString(l) {
return 0, "", fmt.Errorf("parse expression: %v", l)
}
cmd := exec.Command("bc")
cmd.Stdin = strings.NewReader(l + "\n")
var out bytes.Buffer
var er bytes.Buffer
cmd.Stdout = &out
cmd.Stderr = &er
if e := er.String(); e != "" {
log.Errorf("bc: %v", e)
}
if err = cmd.Run(); err != nil {
return
}
f, err = strconv.ParseFloat(strings.TrimSpace(out.String()), 64)
return
}
func length(cs *Map, l string) (f float64, unit string, err error) {
var s string
if l == "auto" || l == "inherit" || l == "initial" || l == "0" {
return 0, "px", nil
}
if strings.Contains(l, "calc") {
return calc(cs, l)
}
for _, suffix := range []string{"px", "%", "rem", "em", "ex", "vw", "vh", "mm"} {
if strings.HasSuffix(l, suffix) {
if s = strings.TrimSuffix(l, suffix); s != "" {
f, err = strconv.ParseFloat(s, 64)
if err != nil {
return 0, "", fmt.Errorf("error parsing '%v': %w", l, err)
}
}
unit = suffix
break
}
}
switch unit {
case "px":
case "rem":
// TODO: use font size from root element
f *= FontBaseSize
case "em", "ex":
// TODO: distinguish between em and ex
if cs == nil {
f *= FontBaseSize
} else {
f *= cs.FontHeight()
}
case "vw":
f *= float64(WindowWidth) / 100.0
case "vh":
f *= float64(WindowHeight) / 100.0
case "%":
if cs == nil {
return 0.0, "%", nil
}
var wp int
if p, ok := cs.DomTree.Parent(); ok {
wp = p.Style().baseWidth()
} else {
log.Printf("%% unit used in root element")
}
f *= 0.01 * float64(wp)
case "mm":
dpi := 100
if dui != nil && dui.Display != nil && dui.Display.DPI != 0 {
dpi = dui.Display.DPI
}
f *= float64(dpi) / 25.4
default:
return f, unit, fmt.Errorf("unknown suffix: %v", l)
}
return
}
func (cs *Map) Height() int {
d, ok := cs.Declarations["height"]
if ok {
f, _, err := length(cs, d.Value)
if err != nil {
log.Errorf("cannot parse height: %v", err)
}
return int(f)
}
return 0
}
func (cs Map) Width() int {
w := cs.width()
if w > 0 {
if d, ok := cs.Declarations["max-width"]; ok {
f, _, err := length(&cs, d.Value)
if err != nil {
log.Errorf("cannot parse width: %v", err)
}
if mw := int(f); 0 < mw && mw < w {
return int(mw)
}
}
}
return w
}
func (cs Map) width() int {
d, ok := cs.Declarations["width"]
if ok {
f, _, err := length(&cs, d.Value)
if err != nil {
log.Errorf("cannot parse width: %v", err)
}
if f > 0 {
return int(f)
}
}
if _, ok := cs.DomTree.Parent(); !ok {
return WindowWidth
}
return 0
}
// baseWidth to calculate relative widths
func (cs Map) baseWidth() int {
if w := cs.Width(); w != 0 {
return w
}
if p, ok := cs.DomTree.Parent(); !ok {
return WindowWidth
} else {
return p.Style().baseWidth()
}
return 0
}
func (cs Map) Css(propName string) string {
d, ok := cs.Declarations[propName]
if !ok {
return ""
}
return d.Value
}
func (cs *Map) CssPx(propName string) (l int, err error) {
d, ok := cs.Declarations[propName]
if !ok {
return 0, fmt.Errorf("property doesn't exist")
}
f, _, err := length(cs, d.Value)
if err != nil {
return 0, err
}
l = int(f)
return
}
func (cs Map) SetCss(k, v string) {
cs.Declarations[k] = css.Declaration{
Property: k,
Value: v,
}
}