mirror of https://github.com/anoshenko/rui.git
142 lines
3.4 KiB
Go
142 lines
3.4 KiB
Go
package rui
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import (
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"strconv"
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)
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const (
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// ImageLoading is the image loading status: in the process of loading
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ImageLoading = 0
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// ImageReady is the image loading status: the image is loaded successfully
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ImageReady = 1
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// ImageLoadingError is the image loading status: an error occurred while loading
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ImageLoadingError = 2
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)
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// Image defines the image that is used for drawing operations on the Canvas.
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type Image interface {
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// URL returns the url of the image
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URL() string
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// LoadingStatus returns the status of the image loading: ImageLoading (0), ImageReady (1), ImageLoadingError (2)
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LoadingStatus() int
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// LoadingError: if LoadingStatus() == ImageLoadingError then returns the error text, "" otherwise
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LoadingError() string
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setLoadingError(err string)
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// Width returns the width of the image in pixels. While LoadingStatus() != ImageReady returns 0
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Width() float64
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// Height returns the height of the image in pixels. While LoadingStatus() != ImageReady returns 0
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Height() float64
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}
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type imageData struct {
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url string
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loadingStatus int
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loadingError string
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width, height float64
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listener func(Image)
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}
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type imageManager struct {
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images map[string]*imageData
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}
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func (image *imageData) URL() string {
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return image.url
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}
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func (image *imageData) LoadingStatus() int {
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return image.loadingStatus
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}
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func (image *imageData) LoadingError() string {
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return image.loadingError
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}
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func (image *imageData) setLoadingError(err string) {
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image.loadingError = err
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}
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func (image *imageData) Width() float64 {
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return image.width
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}
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func (image *imageData) Height() float64 {
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return image.height
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}
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func (manager *imageManager) loadImage(url string, onLoaded func(Image), session Session) Image {
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if manager.images == nil {
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manager.images = make(map[string]*imageData)
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}
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if image, ok := manager.images[url]; ok && image.loadingStatus == ImageReady {
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return image
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}
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image := new(imageData)
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image.url = url
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image.listener = onLoaded
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image.loadingStatus = ImageLoading
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manager.images[url] = image
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session.callFunc("loadImage", url)
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session.sendResponse()
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return image
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}
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func (manager *imageManager) imageLoaded(obj DataObject) {
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if manager.images == nil {
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manager.images = make(map[string]*imageData)
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return
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}
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if url, ok := obj.PropertyValue("url"); ok {
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if image, ok := manager.images[url]; ok {
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image.loadingStatus = ImageReady
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if width, ok := obj.PropertyValue("width"); ok {
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if w, err := strconv.ParseFloat(width, 64); err == nil {
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image.width = w
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}
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}
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if height, ok := obj.PropertyValue("height"); ok {
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if h, err := strconv.ParseFloat(height, 64); err == nil {
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image.height = h
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}
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}
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if image.listener != nil {
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image.listener(image)
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}
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}
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}
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}
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func (manager *imageManager) imageLoadError(obj DataObject) {
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if manager.images == nil {
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manager.images = make(map[string]*imageData)
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return
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}
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if url, ok := obj.PropertyValue("url"); ok {
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if image, ok := manager.images[url]; ok {
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delete(manager.images, url)
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text, _ := obj.PropertyValue("message")
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image.setLoadingError(text)
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if image.listener != nil {
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image.listener(image)
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}
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}
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}
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}
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// LoadImage starts the async image loading by url
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func LoadImage(url string, onLoaded func(Image), session Session) Image {
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if url != "" && url[0] == '@' {
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if image, ok := session.ImageConstant(url[1:]); ok {
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url = image
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}
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}
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return session.imageManager().loadImage(url, onLoaded, session)
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}
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