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Scrollbars can be dragged with the mouse

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This commit is contained in:
Sasha Koshka 2023-01-21 01:15:30 -05:00
parent 3e8523f37a
commit d435f5a6a9
1 changed files with 48 additions and 3 deletions
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51
elements/basic/scrollcontainer.go
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@ -19,6 +19,8 @@ type ScrollContainer struct {
horizontal struct {
exists bool
enabled bool
dragging bool
dragOffset image.Point
gutter image.Rectangle
bar image.Rectangle
}
@ -26,6 +28,8 @@ type ScrollContainer struct {
vertical struct {
exists bool
enabled bool
dragging bool
dragOffset image.Point
gutter image.Rectangle
bar image.Rectangle
}
@ -106,19 +110,40 @@ func (element *ScrollContainer) HandleKeyUp (key tomo.Key, modifiers tomo.Modifi
}
func (element *ScrollContainer) HandleMouseDown (x, y int, button tomo.Button) {
if child, ok := element.child.(tomo.MouseTarget); ok {
point := image.Pt(x, y)
if point.In(element.horizontal.gutter) {
element.horizontal.dragging = true
element.dragHorizontalBar(point)
} else if point.In(element.vertical.gutter) {
element.vertical.dragging = true
element.dragVerticalBar(point)
} else if child, ok := element.child.(tomo.MouseTarget); ok {
child.HandleMouseDown(x, y, button)
}
}
func (element *ScrollContainer) HandleMouseUp (x, y int, button tomo.Button) {
if child, ok := element.child.(tomo.MouseTarget); ok {
if element.horizontal.dragging {
element.horizontal.dragging = false
} else if element.vertical.dragging {
element.vertical.dragging = false
} else if child, ok := element.child.(tomo.MouseTarget); ok {
child.HandleMouseUp(x, y, button)
}
}
func (element *ScrollContainer) HandleMouseMove (x, y int) {
if child, ok := element.child.(tomo.MouseTarget); ok {
if element.horizontal.dragging {
element.dragHorizontalBar(image.Pt(x, y))
} else if element.vertical.dragging {
element.dragVerticalBar(image.Pt(x, y))
} else if child, ok := element.child.(tomo.MouseTarget); ok {
child.HandleMouseMove(x, y)
}
}
@ -324,6 +349,26 @@ func (element *ScrollContainer) drawVerticalBar () {
element.vertical.bar)
}
func (element *ScrollContainer) dragHorizontalBar (mousePosition image.Point) {
scrollX :=
float64(element.child.ScrollContentBounds().Dx()) /
float64(element.horizontal.gutter.Dx()) *
float64 (
mousePosition.X - element.horizontal.bar.Dx() / 2)
scrollY := element.child.ScrollViewportBounds().Min.Y
element.child.ScrollTo(image.Pt(int(scrollX), scrollY))
}
func (element *ScrollContainer) dragVerticalBar (mousePosition image.Point) {
scrollY :=
float64(element.child.ScrollContentBounds().Dy()) /
float64(element.vertical.gutter.Dy()) *
float64 (
mousePosition.Y - element.vertical.bar.Dy() / 2)
scrollX := element.child.ScrollViewportBounds().Min.X
element.child.ScrollTo(image.Pt(scrollX, int(scrollY)))
}
func (element *ScrollContainer) updateMinimumSize () {
width := theme.Padding() * 2
height := theme.Padding() * 2