Improve extensibility of the DiagramWidget

cmd/diagramdemo/main.go

@@ -9,6 +9,7 @@ import (
 
  "fyne.io/fyne/v2"
  "fyne.io/fyne/v2/app"
+ "fyne.io/fyne/v2/canvas"
  "fyne.io/fyne/v2/container"
  "fyne.io/fyne/v2/widget"
 )
@@ -29,6 +30,67 @@ func forceanim(diagramWidget *diagramwidget.DiagramWidget) {
  }
 }
 
+// ModifiedDragNode illustrates how to extend a node. This particular example
+// disables vertical movement and vertical resizing
+type ModifiedDragNode struct {
+ diagramwidget.BaseDiagramNode
+ label *widget.Label
+}
+
+// NewModifiedDragNode returns an instance of an ExtendedNode
+func NewModifiedDragNode(nodeID string, diagramWidget *diagramwidget.DiagramWidget) diagramwidget.DiagramNode {
+ newNode := &ModifiedDragNode{}
+ newNode.label = widget.NewLabel("Vertical Changes Not Alloweed")
+ diagramwidget.InitializeBaseDiagramNode(newNode, diagramWidget, newNode.label, nodeID)
+ newNode.Refresh()
+ return newNode
+}
+
+// Dragged passes the DragEvent to the diagram for processing after removing any Y value changes
+func (en *ModifiedDragNode) Dragged(event *fyne.DragEvent) {
+ modifiedDelta := fyne.Delta{
+ DX: event.Dragged.DX,
+ DY: 0,
+ }
+ modifiedDragEvent := &fyne.DragEvent{
+ PointEvent: event.PointEvent,
+ Dragged: modifiedDelta,
+ }
+ en.GetDiagram().DiagramNodeDragged(&en.BaseDiagramNode, modifiedDragEvent)
+}
+
+// HandleDragged passes the HandleDragged event to the BasseDiagramNode after removing any Y value changes
+func (en *ModifiedDragNode) HandleDragged(handle *diagramwidget.Handle, event *fyne.DragEvent) {
+ modifiedDelta := fyne.Delta{
+ DX: event.Dragged.DX,
+ DY: 0,
+ }
+ modifiedDragEvent := &fyne.DragEvent{
+ PointEvent: event.PointEvent,
+ Dragged: modifiedDelta,
+ }
+ en.BaseDiagramNode.HandleDragged(handle, modifiedDragEvent)
+}
+
+// ModifiedPadsNode removes the default rectangle pad on the perimeter and adds two point pads,
+// one at each side of the node
+type ModifiedPadsNode struct {
+ diagramwidget.BaseDiagramNode
+ label *widget.Label
+}
+
+// NewModifiedPadsNode creates and initializes a ModifiedPadsNode
+func NewModifiedPadsNode(nodeID string, diagramWidget *diagramwidget.DiagramWidget) diagramwidget.DiagramNode {
+ newNode := &ModifiedPadsNode{}
+ newNode.label = widget.NewLabel("Connection pads on left and right")
+ diagramwidget.InitializeBaseDiagramNode(newNode, diagramWidget, newNode.label, nodeID)
+ // Get rid of the default pad on the perimeter
+ newNode.SetConnectionPad(nil, "default")
+ newNode.SetConnectionPad(diagramwidget.NewPointPad(newNode.GetProperties().PadStrokeWidth), "left")
+ newNode.SetConnectionPad(diagramwidget.NewPointPad(newNode.GetProperties().PadStrokeWidth), "right")
+ return newNode
+}
+
 func main() {
  app := app.New()
  w := app.NewWindow("Diagram Demo")
@@ -37,10 +99,19 @@ func main() {
 
  diagramWidget := diagramwidget.NewDiagramWidget("Diagram1")
 
- scrollContainer := container.NewScroll(diagramWidget)
-
  go forceanim(diagramWidget)
 
+ background := canvas.NewCircle(color.RGBA{
+ R: 252,
+ G: 244,
+ B: 3,
+ A: 255,
+ })
+
+ background.Resize(fyne.NewSize(200, 200))
+
+ diagramWidget.SetBackground(background)
+
  // Node 0
  node0Label := widget.NewLabel("Node0")
  node0 := diagramwidget.NewDiagramNode(diagramWidget, node0Label, "Node0")
@@ -91,9 +162,29 @@ func main() {
  }), "Node4")
  node4.Move(fyne.Position{X: 400, Y: 400})
 
- node5 := diagramwidget.NewDiagramNode(diagramWidget, widget.NewLabel("Node5"), "Node5")
+ node5 := diagramwidget.NewDiagramNode(diagramWidget, widget.NewButton("Node5: Toggle Background Graphic", func() {
+ if diagramWidget.GetBackground() == nil {
+ diagramWidget.SetBackground(background)
+ } else {
+ diagramWidget.SetBackground(nil)
+ }
+ }), "Node5")
  node5.Move(fyne.NewPos(600, 200))
 
+ node6 := NewModifiedDragNode("Node6", diagramWidget)
+ node6.Move(fyne.NewPos(500, 0))
+
+ node7 := NewModifiedPadsNode("Node7", diagramWidget)
+ node7Size := node7.Size()
+ halfPointPadSize := diagramwidget.PointPadSize / 2
+ node7Pads := node7.GetConnectionPads()
+ node7DefaultPadPosition := fyne.NewPos(-halfPointPadSize, node7Size.Height/2-halfPointPadSize)
+ node7Pads["left"].Move(node7DefaultPadPosition)
+ node7RightPadPosition := fyne.NewPos(node7Size.Width-halfPointPadSize, node7Size.Height/2-halfPointPadSize)
+ node7Pads["right"].Move(node7RightPadPosition)
+ node7.Move(fyne.NewPos(500, 50))
+ node7.Refresh()
+
  // Link0
  link0 := diagramwidget.NewDiagramLink(diagramWidget, "Link0")
  link0.SetSourcePad(node0.GetEdgePad())
@@ -146,7 +237,15 @@ func main() {
  link5.AddMidpointAnchoredText("linkName", "Link 5")
  link5.AddTargetDecoration(diagramwidget.NewArrowhead())
 
- w.SetContent(scrollContainer)
+ link6 := diagramwidget.NewDiagramLink(diagramWidget, "Link6")
+ link6.SetSourcePad(node6.GetEdgePad())
+ link6.SetTargetPad(node7.GetConnectionPads()["left"])
+
+ link7 := diagramwidget.NewDiagramLink(diagramWidget, "Link7")
+ link7.SetSourcePad(node6.GetEdgePad())
+ link7.SetTargetPad(node7.GetConnectionPads()["right"])
+
+ w.SetContent(diagramWidget)
 
  w.Resize(fyne.NewSize(600, 400))
  w.ShowAndRun()

widget/diagramwidget/anchoredtext.go

@@ -19,7 +19,8 @@ import (
 // move by the same amount
 type AnchoredText struct {
  widget.BaseWidget
- link *BaseDiagramLink
+ diagramElement DiagramElement
+ ID string
  offset r2.Vec2
  referencePosition fyne.Position
  displayedTextBinding binding.String
@@ -30,12 +31,15 @@ type AnchoredText struct {
 // NewAnchoredText creates an textual annotation for a link. After it is created, one of the
 // three Add<position>AnchoredText methods must be called on the link to actually associate the
 // anchored text with the appropriate reference point on the link.
-func NewAnchoredText(text string) *AnchoredText {
+func NewAnchoredText(text string, id ...string) *AnchoredText {
  at := &AnchoredText{
  offset: r2.MakeVec2(0, 0),
  ForegroundColor: theme.ForegroundColor(),
  referencePosition: fyne.Position{X: 0, Y: 0},
  }
+ if len(id) > 0 {
+ at.ID = id[0]
+ }
  at.displayedTextBinding = binding.NewString()
  at.displayedTextBinding.Set(text)
  at.textEntry = widget.NewEntryWithData(at.displayedTextBinding)
@@ -59,16 +63,28 @@ func (at *AnchoredText) CreateRenderer() fyne.WidgetRenderer {
 
 // DataChanged is the callback function for the displayedTextBinding.
 func (at *AnchoredText) DataChanged() {
+ callback := at.diagramElement.GetDiagram().AnchoredTextChangedCallback
+ if callback != nil {
+ callback(at)
+ }
  at.Refresh()
 }
 
 // Displace moves the anchored text relative to its reference position.
 func (at *AnchoredText) Displace(delta fyne.Position) {
  at.Move(at.Position().Add(delta))
+ callback := at.diagramElement.GetDiagram().AnchoredTextChangedCallback
+ if callback != nil {
+ callback(at)
+ }
 }
 
 // DragEnd is one of the required methods for a draggable widget. It just refreshes the widget.
 func (at *AnchoredText) DragEnd() {
+ callback := at.diagramElement.GetDiagram().AnchoredTextChangedCallback
+ if callback != nil {
+ callback(at)
+ }
  at.Refresh()
 }
 
@@ -77,14 +93,33 @@ func (at *AnchoredText) DragEnd() {
 func (at *AnchoredText) Dragged(event *fyne.DragEvent) {
  delta := fyne.Position{X: event.Dragged.DX, Y: event.Dragged.DY}
  at.Move(at.Position().Add(delta))
+ callback := at.diagramElement.GetDiagram().AnchoredTextChangedCallback
+ if callback != nil {
+ callback(at)
+ }
  at.Refresh()
 }
 
+// GetDiagramElement returns the diagram element to which the anchored text belongs
+func (at *AnchoredText) GetDiagramElement() DiagramElement {
+ return at.diagramElement
+}
+
 // GetDisplayedTextBinding returns the binding for the displayed text
 func (at *AnchoredText) GetDisplayedTextBinding() binding.String {
  return at.displayedTextBinding
 }
 
+// GetOffset returns the X and Y values of the anchored text's offset from the reference position
+func (at *AnchoredText) GetOffset() (X float64, Y float64) {
+ return at.offset.X, at.offset.Y
+}
+
+// GetReferencePosition returns the X and Y values of the anchored text's reference position
+func (at *AnchoredText) GetReferencePosition() (X float64, Y float64) {
+ return float64(at.referencePosition.X), float64(at.referencePosition.Y)
+}
+
 // GetTextEntry returns the entry widget
 func (at *AnchoredText) GetTextEntry() *widget.Entry {
  return at.textEntry
@@ -114,8 +149,12 @@ func (at *AnchoredText) MouseOut() {
 // and then calls the normal BaseWidget.Move method.
 func (at *AnchoredText) Move(position fyne.Position) {
  delta := r2.MakeVec2(float64(position.X-at.Position().X), float64(position.Y-at.Position().Y))
- at.offset = at.offset.Add(delta)
- at.BaseWidget.Move(position)
+ newOffset := at.offset.Add(delta)
+ at.SetOffsetNoCallback(newOffset.X, newOffset.Y)
+ callback := at.diagramElement.GetDiagram().AnchoredTextChangedCallback
+ if callback != nil {
+ callback(at)
+ }
 }
 
 // SetForegroundColor sets the text color
@@ -124,13 +163,53 @@ func (at *AnchoredText) SetForegroundColor(fc color.Color) {
  at.Refresh()
 }
 
+// SetOffset sets the X and Y values of the anchored text's offset from the reference position
+func (at *AnchoredText) SetOffset(X float64, Y float64) {
+ if at.offset.X != X || at.offset.Y != Y {
+ at.SetOffsetNoCallback(X, Y)
+ callback := at.diagramElement.GetDiagram().AnchoredTextChangedCallback
+ if callback != nil {
+ callback(at)
+ }
+ }
+}
+
+// SetOffsetNoCallback sets the X and Y values of the anchored text's offset from the reference position
+func (at *AnchoredText) SetOffsetNoCallback(X float64, Y float64) {
+ if at.offset.X != X || at.offset.Y != Y {
+ at.offset.X = X
+ at.offset.Y = Y
+ delta := fyne.Delta{DX: float32(X), DY: float32(Y)}
+ at.BaseWidget.Move(at.referencePosition.Add(delta))
+ }
+}
+
 // SetReferencePosition sets the reference position of the anchored text and calls
 // the BaseWidget.Move() method to actually move the displayed text
 func (at *AnchoredText) SetReferencePosition(position fyne.Position) {
- delta := fyne.Delta{DX: float32(position.X - at.referencePosition.X), DY: float32(position.Y - at.referencePosition.Y)}
- // We don't want to change the offset here, so we call the BaseWidget.Move directly
- at.BaseWidget.Move(at.Position().Add(delta))
- at.referencePosition = position
+ if position != at.referencePosition {
+ at.SetReferencePositionNoCallback(position)
+ callback := at.diagramElement.GetDiagram().AnchoredTextChangedCallback
+ if callback != nil {
+ callback(at)
+ }
+ }
+}
+
+// SetReferencePositionNoCallback sets the reference position of the anchored text and calls
+// the BaseWidget.Move() method to actually move the displayed text
+func (at *AnchoredText) SetReferencePositionNoCallback(position fyne.Position) {
+ if position != at.referencePosition {
+ delta := fyne.Delta{DX: float32(position.X - at.referencePosition.X), DY: float32(position.Y - at.referencePosition.Y)}
+ // We don't want to change the offset here, so we call the BaseWidget.Move directly
+ at.BaseWidget.Move(at.Position().Add(delta))
+ at.referencePosition = position
+ }
+}
+
+// SetText sets the anchored text without invoking the callback
+func (at *AnchoredText) SetText(text string) {
+ at.displayedTextBinding.Set(text)
 }
 
 // anchoredTextRenderer