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rui/background.go

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20 KiB
Go

package rui
import "strings"
const (
// NoRepeat is value of the Repeat property of an background image:
// The image is not repeated (and hence the background image painting area
// will not necessarily be entirely covered). The position of the non-repeated
// background image is defined by the background-position CSS property.
NoRepeat = 0
// RepeatXY is value of the Repeat property of an background image:
// The image is repeated as much as needed to cover the whole background
// image painting area. The last image will be clipped if it doesn't fit.
RepeatXY = 1
// RepeatX is value of the Repeat property of an background image:
// The image is repeated horizontally as much as needed to cover
// the whole width background image painting area. The image is not repeated vertically.
// The last image will be clipped if it doesn't fit.
RepeatX = 2
// RepeatY is value of the Repeat property of an background image:
// The image is repeated vertically as much as needed to cover
// the whole height background image painting area. The image is not repeated horizontally.
// The last image will be clipped if it doesn't fit.
RepeatY = 3
// RepeatRound is value of the Repeat property of an background image:
// As the allowed space increases in size, the repeated images will stretch (leaving no gaps)
// until there is room (space left >= half of the image width) for another one to be added.
// When the next image is added, all of the current ones compress to allow room.
RepeatRound = 4
// RepeatSpace is value of the Repeat property of an background image:
// The image is repeated as much as possible without clipping. The first and last images
// are pinned to either side of the element, and whitespace is distributed evenly between the images.
RepeatSpace = 5
// ScrollAttachment is value of the Attachment property of an background image:
// The background is fixed relative to the element itself and does not scroll with its contents.
// (It is effectively attached to the element's border.)
ScrollAttachment = 0
// FixedAttachment is value of the Attachment property of an background image:
// The background is fixed relative to the viewport. Even if an element has
// a scrolling mechanism, the background doesn't move with the element.
FixedAttachment = 1
// LocalAttachment is value of the Attachment property of an background image:
// The background is fixed relative to the element's contents. If the element has a scrolling mechanism,
// the background scrolls with the element's contents, and the background painting area
// and background positioning area are relative to the scrollable area of the element
// rather than to the border framing them.
LocalAttachment = 2
// BorderBoxClip is value of the BackgroundClip property:
// The background extends to the outside edge of the border (but underneath the border in z-ordering).
BorderBoxClip = 0
// PaddingBoxClip is value of the BackgroundClip property:
// The background extends to the outside edge of the padding. No background is drawn beneath the border.
PaddingBoxClip = 1
// ContentBoxClip is value of the BackgroundClip property:
// The background is painted within (clipped to) the content box.
ContentBoxClip = 2
// ToTopGradient is value of the Direction property of a linear gradient. The value is equivalent to the 0deg angle
ToTopGradient = 0
// ToRightTopGradient is value of the Direction property of a linear gradient.
ToRightTopGradient = 1
// ToRightGradient is value of the Direction property of a linear gradient. The value is equivalent to the 90deg angle
ToRightGradient = 2
// ToRightBottomGradient is value of the Direction property of a linear gradient.
ToRightBottomGradient = 3
// ToBottomGradient is value of the Direction property of a linear gradient. The value is equivalent to the 180deg angle
ToBottomGradient = 4
// ToLeftBottomGradient is value of the Direction property of a linear gradient.
ToLeftBottomGradient = 5
// ToLeftGradient is value of the Direction property of a linear gradient. The value is equivalent to the 270deg angle
ToLeftGradient = 6
// ToLeftTopGradient is value of the Direction property of a linear gradient.
ToLeftTopGradient = 7
// EllipseGradient is value of the Shape property of a radial gradient background:
// the shape is an axis-aligned ellipse
EllipseGradient = 0
// CircleGradient is value of the Shape property of a radial gradient background:
// the gradient's shape is a circle with constant radius
CircleGradient = 1
// ClosestSideGradient is value of the Radius property of a radial gradient background:
// The gradient's ending shape meets the side of the box closest to its center (for circles)
// or meets both the vertical and horizontal sides closest to the center (for ellipses).
ClosestSideGradient = 0
// ClosestCornerGradient is value of the Radius property of a radial gradient background:
// The gradient's ending shape is sized so that it exactly meets the closest corner
// of the box from its center.
ClosestCornerGradient = 1
// FarthestSideGradient is value of the Radius property of a radial gradient background:
// Similar to closest-side, except the ending shape is sized to meet the side of the box
// farthest from its center (or vertical and horizontal sides).
FarthestSideGradient = 2
// FarthestCornerGradient is value of the Radius property of a radial gradient background:
// The default value, the gradient's ending shape is sized so that it exactly meets
// the farthest corner of the box from its center.
FarthestCornerGradient = 3
)
// BackgroundElement describes the background element.
type BackgroundElement interface {
Properties
cssStyle(session Session) string
Tag() string
}
type backgroundElement struct {
propertyList
}
type backgroundImage struct {
backgroundElement
}
// BackgroundGradientPoint define point on gradient straight line
type BackgroundGradientPoint struct {
// Pos - the distance from the start of the gradient straight line
Pos SizeUnit
// Color - the color of the point
Color Color
}
type backgroundGradient struct {
backgroundElement
}
type backgroundLinearGradient struct {
backgroundGradient
}
type backgroundRadialGradient struct {
backgroundGradient
}
// NewBackgroundImage creates the new background image
func createBackground(obj DataObject) BackgroundElement {
var result BackgroundElement = nil
switch obj.Tag() {
case "image":
image := new(backgroundImage)
image.properties = map[string]interface{}{}
result = image
case "linear-gradient":
gradient := new(backgroundLinearGradient)
gradient.properties = map[string]interface{}{}
result = gradient
case "radial-gradient":
gradient := new(backgroundRadialGradient)
gradient.properties = map[string]interface{}{}
result = gradient
default:
return nil
}
count := obj.PropertyCount()
for i := 0; i < count; i++ {
if node := obj.Property(i); node.Type() == TextNode {
if value := node.Text(); value != "" {
result.Set(node.Tag(), value)
}
}
}
return result
}
// NewBackgroundImage creates the new background image
func NewBackgroundImage(params Params) BackgroundElement {
result := new(backgroundImage)
result.properties = map[string]interface{}{}
for tag, value := range params {
result.Set(tag, value)
}
return result
}
// NewBackgroundLinearGradient creates the new background linear gradient
func NewBackgroundLinearGradient(params Params) BackgroundElement {
result := new(backgroundLinearGradient)
result.properties = map[string]interface{}{}
for tag, value := range params {
result.Set(tag, value)
}
return result
}
// NewBackgroundRadialGradient creates the new background radial gradient
func NewBackgroundRadialGradient(params Params) BackgroundElement {
result := new(backgroundRadialGradient)
result.properties = map[string]interface{}{}
for tag, value := range params {
result.Set(tag, value)
}
return result
}
func (image *backgroundImage) Tag() string {
return "image"
}
func (image *backgroundImage) normalizeTag(tag string) string {
tag = strings.ToLower(tag)
switch tag {
case "source":
tag = Source
case Fit:
tag = backgroundFit
case HorizontalAlign:
tag = ImageHorizontalAlign
case VerticalAlign:
tag = ImageVerticalAlign
}
return tag
}
func (image *backgroundImage) Set(tag string, value interface{}) bool {
tag = image.normalizeTag(tag)
switch tag {
case Attachment, Width, Height, Repeat, ImageHorizontalAlign, ImageVerticalAlign,
backgroundFit, Source:
return image.backgroundElement.Set(tag, value)
}
return false
}
func (image *backgroundImage) Get(tag string) interface{} {
return image.backgroundElement.Get(image.normalizeTag(tag))
}
func (image *backgroundImage) cssStyle(session Session) string {
if src, ok := stringProperty(image, Source, session); ok && src != "" {
buffer := allocStringBuilder()
defer freeStringBuilder(buffer)
buffer.WriteString(`url(`)
buffer.WriteString(src)
buffer.WriteRune(')')
attachment, _ := enumProperty(image, Attachment, session, NoRepeat)
values := enumProperties[Attachment].values
if attachment > 0 && attachment < len(values) {
buffer.WriteRune(' ')
buffer.WriteString(values[attachment])
}
align, _ := enumProperty(image, ImageHorizontalAlign, session, LeftAlign)
values = enumProperties[ImageHorizontalAlign].values
if align >= 0 && align < len(values) {
buffer.WriteRune(' ')
buffer.WriteString(values[align])
} else {
buffer.WriteString(` left`)
}
align, _ = enumProperty(image, ImageVerticalAlign, session, TopAlign)
values = enumProperties[ImageVerticalAlign].values
if align >= 0 && align < len(values) {
buffer.WriteRune(' ')
buffer.WriteString(values[align])
} else {
buffer.WriteString(` top`)
}
fit, _ := enumProperty(image, backgroundFit, session, NoneFit)
values = enumProperties[backgroundFit].values
if fit > 0 && fit < len(values) {
buffer.WriteString(` / `)
buffer.WriteString(values[fit])
} else {
width, _ := sizeProperty(image, Width, session)
height, _ := sizeProperty(image, Height, session)
if width.Type != Auto || height.Type != Auto {
buffer.WriteString(` / `)
buffer.WriteString(width.cssString("auto"))
buffer.WriteRune(' ')
buffer.WriteString(height.cssString("auto"))
}
}
repeat, _ := enumProperty(image, Repeat, session, NoRepeat)
values = enumProperties[Repeat].values
if repeat >= 0 && repeat < len(values) {
buffer.WriteRune(' ')
buffer.WriteString(values[repeat])
} else {
buffer.WriteString(` no-repeat`)
}
return buffer.String()
}
return ""
}
func (gradient *backgroundGradient) Set(tag string, value interface{}) bool {
switch tag = strings.ToLower(tag); tag {
case Repeat:
return gradient.setBoolProperty(tag, value)
case Gradient:
switch value := value.(type) {
case string:
if value != "" {
elements := strings.Split(value, `,`)
if count := len(elements); count > 1 {
points := make([]interface{}, count)
for i, element := range elements {
if strings.Contains(element, "@") {
points[i] = element
} else {
var point BackgroundGradientPoint
if point.setValue(element) {
points[i] = point
} else {
ErrorLogF("Invalid gradient element #%d: %s", i, element)
return false
}
}
}
gradient.properties[Gradient] = points
return true
}
text := strings.Trim(value, " \n\r\t")
if text[0] == '@' {
gradient.properties[Gradient] = text
return true
}
}
case []BackgroundGradientPoint:
if len(value) >= 2 {
gradient.properties[Gradient] = value
return true
}
case []Color:
count := len(value)
if count >= 2 {
points := make([]BackgroundGradientPoint, count)
for i, color := range value {
points[i].Color = color
points[i].Pos = AutoSize()
}
gradient.properties[Gradient] = points
return true
}
case []GradientPoint:
count := len(value)
if count >= 2 {
points := make([]BackgroundGradientPoint, count)
for i, point := range value {
points[i].Color = point.Color
points[i].Pos = Percent(point.Offset * 100)
}
gradient.properties[Gradient] = points
return true
}
case []interface{}:
if count := len(value); count > 1 {
points := make([]interface{}, count)
for i, element := range value {
switch element := element.(type) {
case string:
if strings.Contains(element, "@") {
points[i] = element
} else {
var point BackgroundGradientPoint
if !point.setValue(element) {
ErrorLogF("Invalid gradient element #%d: %s", i, element)
return false
}
points[i] = point
}
case BackgroundGradientPoint:
points[i] = element
case GradientPoint:
points[i] = BackgroundGradientPoint{Color: element.Color, Pos: Percent(element.Offset * 100)}
case Color:
points[i] = BackgroundGradientPoint{Color: element, Pos: AutoSize()}
default:
ErrorLogF("Invalid gradient element #%d: %v", i, element)
return false
}
}
gradient.properties[Gradient] = points
return true
}
}
default:
ErrorLogF("Invalid gradient %v", value)
return false
}
return gradient.backgroundElement.Set(tag, value)
}
func (point *BackgroundGradientPoint) setValue(value string) bool {
var ok bool
switch elements := strings.Split(value, `:`); len(elements) {
case 2:
if point.Color, ok = StringToColor(elements[0]); !ok {
return false
}
if point.Pos, ok = StringToSizeUnit(elements[1]); !ok {
return false
}
case 1:
if point.Color, ok = StringToColor(elements[0]); !ok {
return false
}
point.Pos = AutoSize()
default:
return false
}
return false
}
func (gradient *backgroundGradient) writeGradient(session Session, buffer *strings.Builder) bool {
value, ok := gradient.properties[Gradient]
if !ok {
return false
}
points := []BackgroundGradientPoint{}
switch value := value.(type) {
case string:
if text, ok := session.resolveConstants(value); ok && text != "" {
elements := strings.Split(text, `,`)
points := make([]BackgroundGradientPoint, len(elements))
for i, element := range elements {
if !points[i].setValue(element) {
ErrorLogF(`Invalid gradient point #%d: "%s"`, i, element)
return false
}
}
} else {
ErrorLog(`Invalid gradient: ` + value)
return false
}
case []BackgroundGradientPoint:
points = value
case []interface{}:
points = make([]BackgroundGradientPoint, len(value))
for i, element := range value {
switch element := element.(type) {
case string:
if text, ok := session.resolveConstants(element); ok && text != "" {
if !points[i].setValue(text) {
ErrorLogF(`Invalid gradient point #%d: "%s"`, i, text)
return false
}
} else {
ErrorLogF(`Invalid gradient point #%d: "%s"`, i, text)
return false
}
case BackgroundGradientPoint:
points[i] = element
}
}
}
if len(points) > 0 {
for i, point := range points {
if i > 0 {
buffer.WriteString(`, `)
}
buffer.WriteString(point.Color.cssString())
if point.Pos.Type != Auto {
buffer.WriteRune(' ')
buffer.WriteString(point.Pos.cssString(""))
}
}
return true
}
return false
}
func (gradient *backgroundLinearGradient) Tag() string {
return "linear-gradient"
}
func (gradient *backgroundLinearGradient) Set(tag string, value interface{}) bool {
if tag == Direction {
switch value := value.(type) {
case AngleUnit:
gradient.properties[Direction] = value
return true
case string:
var angle AngleUnit
if ok, _ := angle.setValue(value); ok {
gradient.properties[Direction] = angle
return true
}
}
return gradient.setEnumProperty(tag, value, enumProperties[Direction].values)
}
return gradient.backgroundGradient.Set(tag, value)
}
func (gradient *backgroundLinearGradient) cssStyle(session Session) string {
buffer := allocStringBuilder()
defer freeStringBuilder(buffer)
if repeating, _ := boolProperty(gradient, Repeating, session); repeating {
buffer.WriteString(`repeating-linear-gradient(`)
} else {
buffer.WriteString(`linear-gradient(`)
}
if value, ok := gradient.properties[Direction]; ok {
switch value := value.(type) {
case string:
if text, ok := session.resolveConstants(value); ok {
direction := enumProperties[Direction]
if n, ok := enumStringToInt(text, direction.values, false); ok {
buffer.WriteString(direction.cssValues[n])
buffer.WriteString(", ")
} else {
if angle, ok := StringToAngleUnit(text); ok {
buffer.WriteString(angle.cssString())
buffer.WriteString(", ")
} else {
ErrorLog(`Invalid linear gradient direction: ` + text)
}
}
} else {
ErrorLog(`Invalid linear gradient direction: ` + value)
}
case int:
values := enumProperties[Direction].cssValues
if value >= 0 && value < len(values) {
buffer.WriteString(values[value])
buffer.WriteString(", ")
} else {
ErrorLogF(`Invalid linear gradient direction: %d`, value)
}
case AngleUnit:
buffer.WriteString(value.cssString())
buffer.WriteString(", ")
}
}
if !gradient.writeGradient(session, buffer) {
return ""
}
buffer.WriteString(") ")
return buffer.String()
}
func (gradient *backgroundRadialGradient) Tag() string {
return "radial-gradient"
}
func (gradient *backgroundRadialGradient) normalizeTag(tag string) string {
tag = strings.ToLower(tag)
switch tag {
case Radius:
tag = RadialGradientRadius
case Shape:
tag = RadialGradientShape
case "x-center":
tag = CenterX
case "y-center":
tag = CenterY
}
return tag
}
func (gradient *backgroundRadialGradient) Set(tag string, value interface{}) bool {
tag = gradient.normalizeTag(tag)
switch tag {
case RadialGradientRadius:
switch value := value.(type) {
case string, SizeUnit:
return gradient.propertyList.Set(RadialGradientRadius, value)
case int:
n := value
if n >= 0 && n < len(enumProperties[RadialGradientRadius].values) {
return gradient.propertyList.Set(RadialGradientRadius, value)
}
}
ErrorLogF(`Invalid value of "%s" property: %v`, tag, value)
case RadialGradientShape:
return gradient.propertyList.Set(RadialGradientShape, value)
case CenterX, CenterY:
return gradient.propertyList.Set(tag, value)
}
return gradient.backgroundGradient.Set(tag, value)
}
func (gradient *backgroundRadialGradient) Get(tag string) interface{} {
return gradient.backgroundGradient.Get(gradient.normalizeTag(tag))
}
func (gradient *backgroundRadialGradient) cssStyle(session Session) string {
buffer := allocStringBuilder()
defer freeStringBuilder(buffer)
if repeating, _ := boolProperty(gradient, Repeating, session); repeating {
buffer.WriteString(`repeating-radial-gradient(`)
} else {
buffer.WriteString(`radial-gradient(`)
}
if shape, ok := enumProperty(gradient, RadialGradientShape, session, EllipseGradient); ok && shape == CircleGradient {
buffer.WriteString(`circle `)
} else {
buffer.WriteString(`ellipse `)
}
if value, ok := gradient.properties[RadialGradientRadius]; ok {
switch value := value.(type) {
case string:
if text, ok := session.resolveConstants(value); ok {
values := enumProperties[RadialGradientRadius]
if n, ok := enumStringToInt(text, values.values, false); ok {
buffer.WriteString(values.cssValues[n])
buffer.WriteString(" ")
} else {
if r, ok := StringToSizeUnit(text); ok && r.Type != Auto {
buffer.WriteString(r.cssString(""))
buffer.WriteString(" ")
} else {
ErrorLog(`Invalid linear gradient radius: ` + text)
}
}
} else {
ErrorLog(`Invalid linear gradient radius: ` + value)
}
case int:
values := enumProperties[RadialGradientRadius].cssValues
if value >= 0 && value < len(values) {
buffer.WriteString(values[value])
buffer.WriteString(" ")
} else {
ErrorLogF(`Invalid linear gradient radius: %d`, value)
}
case SizeUnit:
if value.Type != Auto {
buffer.WriteString(value.cssString(""))
buffer.WriteString(" ")
}
}
}
x, _ := sizeProperty(gradient, CenterX, session)
y, _ := sizeProperty(gradient, CenterX, session)
if x.Type != Auto || y.Type != Auto {
buffer.WriteString("at ")
buffer.WriteString(x.cssString("50%"))
buffer.WriteString(" ")
buffer.WriteString(y.cssString("50%"))
}
buffer.WriteString(", ")
if !gradient.writeGradient(session, buffer) {
return ""
}
buffer.WriteString(") ")
return buffer.String()
}