163 lines
3.9 KiB
Go
163 lines
3.9 KiB
Go
package core
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import "image"
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import "image/color"
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import "git.tebibyte.media/sashakoshka/tomo"
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// Core is a struct that implements some core functionality common to most
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// widgets. It is meant to be embedded directly into a struct.
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type Core struct {
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canvas *image.RGBA
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parent tomo.Element
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metrics struct {
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minimumWidth int
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minimumHeight int
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}
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selectable bool
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selected bool
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hooks tomo.ParentHooks
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}
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// NewCore creates a new element core and its corresponding control.
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func NewCore (parent tomo.Element) (core *Core, control CoreControl) {
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core = &Core { parent: parent }
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control = CoreControl { core: core }
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return
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}
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func (core Core) ColorModel () (model color.Model) {
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return color.RGBAModel
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}
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func (core Core) At (x, y int) (pixel color.Color) {
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if core.canvas == nil { return color.RGBA { } }
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pixel = core.canvas.At(x, y)
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return
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}
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func (core Core) RGBAAt (x, y int) (pixel color.RGBA) {
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if core.canvas == nil { return color.RGBA { } }
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pixel = core.canvas.RGBAAt(x, y)
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return
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}
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func (core Core) Bounds () (bounds image.Rectangle) {
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if core.canvas != nil { bounds = core.canvas.Bounds() }
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return
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}
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func (core Core) Selectable () (selectable bool) {
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return core.selectable
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}
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func (core Core) Selected () (selected bool) {
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return core.selected
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}
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func (core Core) AdvanceSelection (direction int) (ok bool) {
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return
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}
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func (core *Core) SetParentHooks (hooks tomo.ParentHooks) {
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core.hooks = hooks
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}
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func (core Core) MinimumSize () (width, height int) {
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return core.metrics.minimumWidth, core.metrics.minimumHeight
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}
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// CoreControl is a struct that can exert control over a control struct. It can
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// be used as a canvas. It must not be directly embedded into an element, but
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// instead kept as a private member.
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type CoreControl struct {
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*image.RGBA
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core *Core
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}
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func (control CoreControl) HasImage () (has bool) {
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has = control.RGBA != nil
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return
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}
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func (control CoreControl) Select () {
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control.core.hooks.RunSelectionRequest()
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}
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func (control CoreControl) SetSelected (selected bool) {
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if !control.core.selectable { return }
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control.core.selected = selected
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}
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func (control CoreControl) SetSelectable (selectable bool) {
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if control.core.selectable == selectable { return }
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control.core.selectable = selectable
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if !selectable { control.core.selected = false }
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control.core.hooks.RunSelectabilityChange(selectable)
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}
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func (control CoreControl) PushRegion (bounds image.Rectangle) {
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control.core.hooks.RunDraw(control.SubImage(bounds).(*image.RGBA))
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}
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func (control CoreControl) PushAll () {
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control.PushRegion(control.Bounds())
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}
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func (control *CoreControl) AllocateCanvas (width, height int) {
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core := control.core
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width, height, _ = control.ConstrainSize(width, height)
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core.canvas = image.NewRGBA(image.Rect (0, 0, width, height))
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control.RGBA = core.canvas
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}
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func (control CoreControl) SetMinimumSize (width, height int) {
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core := control.core
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if width == core.metrics.minimumWidth &&
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height == core.metrics.minimumHeight {
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return
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}
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core.metrics.minimumWidth = width
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core.metrics.minimumHeight = height
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core.hooks.RunMinimumSizeChange(width, height)
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// if there is an image buffer, and the current size is less
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// than this new minimum size, send core.parent a resize event.
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if control.HasImage() {
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bounds := control.Bounds()
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imageWidth,
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imageHeight,
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constrained := control.ConstrainSize (
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bounds.Dx(),
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bounds.Dy())
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if constrained {
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core.parent.Handle (tomo.EventResize {
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Width: imageWidth,
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Height: imageHeight,
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})
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}
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}
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}
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func (control CoreControl) ConstrainSize (
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inWidth, inHeight int,
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) (
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outWidth, outHeight int,
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constrained bool,
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) {
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core := control.core
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outWidth = inWidth
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outHeight = inHeight
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if outWidth < core.metrics.minimumWidth {
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outWidth = core.metrics.minimumWidth
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constrained = true
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}
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if outHeight < core.metrics.minimumHeight {
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outHeight = core.metrics.minimumHeight
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constrained = true
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}
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return
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}
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