ref: 9d5388d05404585cffbf9092b83301e507110a7d
dir: /browser/scroll.go/
package browser
// Original code from github.com/mjl-/duit
//
// Copyright 2018 Mechiel Lukkien mechiel@ueber.net
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
import (
"fmt"
"image"
"math"
"9fans.net/go/draw"
"github.com/mjl-/duit"
)
// Scroll shows a part of its single child, typically a box, and lets you scroll the content.
type Scroll struct {
Kid duit.Kid
Height int // < 0 means full height, 0 means as much as necessary, >0 means exactly that many lowdpi pixels
r image.Rectangle // entire ui
barR image.Rectangle
barActiveR image.Rectangle
childR image.Rectangle
Offset int // current scroll offset in pixels
img *draw.Image // for child to draw on
scrollbarSize int
lastMouseUI duit.UI
drawOffset int
}
var _ duit.UI = &Scroll{}
// NewScroll returns a full-height scroll bar containing ui.
func NewScroll(ui duit.UI) *Scroll {
return &Scroll{Height: -1, Kid: duit.Kid{UI: ui}}
}
func (ui *Scroll) Layout(dui *duit.DUI, self *duit.Kid, sizeAvail image.Point, force bool) {
debugLayout(dui, self)
if self.Layout == duit.Clean && !force {
return
}
self.Layout = duit.Clean
self.Draw = duit.Dirty
// todo: be smarter about DirtyKid
ui.scrollbarSize = dui.Scale(duit.ScrollbarSize)
scaledHeight := dui.Scale(ui.Height)
if scaledHeight > 0 && scaledHeight < sizeAvail.Y {
sizeAvail.Y = scaledHeight
}
ui.r = rect(sizeAvail)
ui.barR = ui.r
ui.barR.Max.X = ui.barR.Min.X + ui.scrollbarSize
ui.childR = ui.r
ui.childR.Min.X = ui.barR.Max.X
// todo: only force when sizeAvail or childR changed?
ui.Kid.UI.Layout(dui, &ui.Kid, image.Pt(ui.r.Dx()-ui.barR.Dx(), ui.r.Dy()), force)
ui.Kid.Layout = duit.Clean
ui.Kid.Draw = duit.Dirty
kY := ui.Kid.R.Dy()
if ui.r.Dy() > kY && ui.Height == 0 {
ui.barR.Max.Y = kY
ui.r.Max.Y = kY
ui.childR.Max.Y = kY
}
self.R = rect(ui.r.Size())
}
func (ui *Scroll) Draw(dui *duit.DUI, self *duit.Kid, img *draw.Image, orig image.Point, m draw.Mouse, force bool) {
debugDraw(dui, self)
if self.Draw == duit.Clean {
return
}
self.Draw = duit.Clean
if ui.r.Empty() {
return
}
ui.scroll(0)
barHover := m.In(ui.barR)
bg := dui.ScrollBGNormal
vis := dui.ScrollVisibleNormal
if barHover {
bg = dui.ScrollBGHover
vis = dui.ScrollVisibleHover
}
h := ui.r.Dy()
uih := ui.Kid.R.Dy()
if uih > h {
barR := ui.barR.Add(orig)
img.Draw(barR, bg, nil, image.ZP)
barH := h * h / uih
barY := ui.Offset * h / uih
ui.barActiveR = ui.barR
ui.barActiveR.Min.Y += barY
ui.barActiveR.Max.Y = ui.barActiveR.Min.Y + barH
barActiveR := ui.barActiveR.Add(orig)
barActiveR.Max.X -= 1 // unscaled
img.Draw(barActiveR, vis, nil, image.ZP)
}
// draw child ui
if ui.childR.Empty() {
return
}
d := math.Abs(float64(ui.drawOffset - ui.Offset))
if d > float64(ui.r.Max.Y) {
ui.Kid.Draw = duit.Dirty
}
if ui.img == nil || ui.drawRect().Size() != ui.img.R.Size() || ui.Kid.Draw == duit.Dirty {
var err error
if ui.img != nil {
ui.img.Free()
ui.img = nil
}
ui.Kid.Draw = duit.Dirty
if ui.Kid.R.Dx() == 0 || ui.Kid.R.Dy() == 0 {
return
}
ui.img, err = dui.Display.AllocImage(ui.drawRect(), draw.ARGB32, false, dui.BackgroundColor)
if duitError(dui, err, "allocimage") {
return
}
ui.drawOffset = ui.Offset
} else if ui.Kid.Draw == duit.Dirty {
ui.img.Draw(ui.img.R, dui.Background, nil, image.ZP)
}
m.Point = m.Point.Add(image.Pt(-ui.childR.Min.X, ui.Offset))
if ui.Kid.Draw != duit.Clean {
if force {
ui.Kid.Draw = duit.Dirty
}
ui.Kid.UI.Draw(dui, &ui.Kid, ui.img, image.ZP, m, ui.Kid.Draw == duit.Dirty)
ui.Kid.Draw = duit.Clean
}
img.Draw(ui.childR.Add(orig), ui.img, nil, image.Pt(0, ui.Offset))
}
// Allocate only an image buffer of view size ui.r
// - which is translated by scroll offset ui.Offset - instead
// of whole Kid view size ui.Kid.R which leads to much
// faster render times for large pages. Add same size rectangles
// above/below to decrease flickering.
func (ui *Scroll) drawRect() image.Rectangle {
if 2*ui.r.Dy() > ui.Kid.R.Dy() {
return ui.Kid.R
}
r := image.Rectangle{
Min: ui.r.Min,
Max: image.Point{
ui.r.Max.X,
3*ui.r.Max.Y,
},
}
r = r.Add(image.Point{X:0, Y:ui.Offset-ui.r.Max.Y})
if r.Min.Y > ui.Offset {
r.Min.Y -= ui.Offset
}
return r
}
func (ui *Scroll) scroll(delta int) bool {
o := ui.Offset
ui.Offset += delta
ui.Offset = maximum(0, ui.Offset)
ui.Offset = minimum(ui.Offset, maximum(0, ui.Kid.R.Dy()-ui.childR.Dy()))
return o != ui.Offset
}
func (ui *Scroll) scrollKey(k rune) (consumed bool) {
switch k {
case draw.KeyUp:
return ui.scroll(-50)
case draw.KeyDown:
return ui.scroll(50)
case draw.KeyPageUp:
return ui.scroll(-200)
case draw.KeyPageDown:
return ui.scroll(200)
}
return false
}
func (ui *Scroll) scrollMouse(m draw.Mouse, scrollOnly bool) (consumed bool) {
switch m.Buttons {
case duit.Button4:
return ui.scroll(-m.Y / 4)
case duit.Button5:
return ui.scroll(m.Y / 4)
}
if scrollOnly {
return false
}
switch m.Buttons {
case duit.Button1:
return ui.scroll(-m.Y)
case duit.Button2:
Offset := m.Y * ui.Kid.R.Dy() / ui.barR.Dy()
OffsetMax := ui.Kid.R.Dy() - ui.childR.Dy()
Offset = maximum(0, minimum(Offset, OffsetMax))
o := ui.Offset
ui.Offset = Offset
return o != ui.Offset
case duit.Button3:
return ui.scroll(m.Y)
}
return false
}
func (ui *Scroll) result(dui *duit.DUI, self *duit.Kid, r *duit.Result, scrolled bool) {
if ui.Kid.Layout != duit.Clean {
ui.Kid.UI.Layout(dui, &ui.Kid, ui.childR.Size(), false)
ui.Kid.Layout = duit.Clean
ui.Kid.Draw = duit.Dirty
self.Draw = duit.Dirty
} else if ui.Kid.Draw != duit.Clean || scrolled {
self.Draw = duit.Dirty
}
}
func (ui *Scroll) Mouse(dui *duit.DUI, self *duit.Kid, m draw.Mouse, origM draw.Mouse, orig image.Point) (r duit.Result) {
if m.Point.In(ui.barR) {
r.Hit = ui
r.Consumed = ui.scrollMouse(m, false)
self.Draw = duit.Dirty
return
}
if m.Point.In(ui.childR) {
nOrigM := origM
nOrigM.Point = nOrigM.Point.Add(image.Pt(-ui.scrollbarSize, ui.Offset))
nm := m
nm.Point = nm.Point.Add(image.Pt(-ui.scrollbarSize, ui.Offset))
r = ui.Kid.UI.Mouse(dui, &ui.Kid, nm, nOrigM, image.ZP)
ui.warpScroll(dui, self, r.Warp, orig)
scrolled := false
if !r.Consumed {
scrolled = ui.scrollMouse(m, true)
r.Consumed = scrolled
}
ui.result(dui, self, &r, scrolled)
if r.Hit != ui.lastMouseUI {
if r.Hit != nil {
ui.Mark(self, r.Hit, false)
}
if ui.lastMouseUI != nil {
ui.Mark(self, ui.lastMouseUI, false)
}
}
ui.lastMouseUI = r.Hit
}
return
}
func (ui *Scroll) Key(dui *duit.DUI, self *duit.Kid, k rune, m draw.Mouse, orig image.Point) (r duit.Result) {
if m.Point.In(ui.barR) {
r.Hit = ui
r.Consumed = ui.scrollKey(k)
if r.Consumed {
self.Draw = duit.Dirty
}
}
if m.Point.In(ui.childR) {
m.Point = m.Point.Add(image.Pt(-ui.scrollbarSize, ui.Offset))
r = ui.Kid.UI.Key(dui, &ui.Kid, k, m, image.ZP)
ui.warpScroll(dui, self, r.Warp, orig)
scrolled := false
if !r.Consumed {
scrolled = ui.scrollKey(k)
r.Consumed = scrolled
}
ui.result(dui, self, &r, scrolled)
}
return
}
func (ui *Scroll) warpScroll(dui *duit.DUI, self *duit.Kid, warp *image.Point, orig image.Point) {
if warp == nil {
return
}
Offset := ui.Offset
if warp.Y < ui.Offset {
ui.Offset = maximum(0, warp.Y-dui.Scale(40))
} else if warp.Y > ui.Offset+ui.r.Dy() {
ui.Offset = minimum(ui.Kid.R.Dy()-ui.r.Dy(), warp.Y+dui.Scale(40)-ui.r.Dy())
}
if Offset != ui.Offset {
if self != nil {
self.Draw = duit.Dirty
} else {
dui.MarkDraw(ui)
}
}
warp.Y -= ui.Offset
warp.X += orig.X + ui.scrollbarSize
warp.Y += orig.Y
}
func (ui *Scroll) _focus(dui *duit.DUI, p *image.Point) *image.Point {
if p == nil {
return nil
}
pp := p.Add(ui.childR.Min)
p = &pp
ui.warpScroll(dui, nil, p, image.ZP)
return p
}
func (ui *Scroll) FirstFocus(dui *duit.DUI, self *duit.Kid) *image.Point {
p := ui.Kid.UI.FirstFocus(dui, &ui.Kid)
return ui._focus(dui, p)
}
func (ui *Scroll) Focus(dui *duit.DUI, self *duit.Kid, o duit.UI) *image.Point {
if o == ui {
p := image.Pt(minimum(ui.scrollbarSize/2, ui.r.Dx()), minimum(ui.scrollbarSize/2, ui.r.Dy()))
return &p
}
p := ui.Kid.UI.Focus(dui, &ui.Kid, o)
return ui._focus(dui, p)
}
func (ui *Scroll) Mark(self *duit.Kid, o duit.UI, forLayout bool) (marked bool) {
if self.Mark(o, forLayout) {
return true
}
marked = ui.Kid.UI.Mark(&ui.Kid, o, forLayout)
if marked {
if forLayout {
if self.Layout == duit.Clean {
self.Layout = duit.DirtyKid
}
} else {
if self.Layout == duit.Clean {
self.Draw = duit.DirtyKid
}
}
}
return
}
func (ui *Scroll) Print(self *duit.Kid, indent int) {
what := fmt.Sprintf("Scroll Offset=%d childR=%v", ui.Offset, ui.childR)
duit.PrintUI(what, self, indent)
ui.Kid.UI.Print(&ui.Kid, indent+1)
}
//////////////////////
// //
// helper functions //
// //
//////////////////////
func pt(v int) image.Point {
return image.Point{v, v}
}
func rect(p image.Point) image.Rectangle {
return image.Rectangle{image.ZP, p}
}
func extendY(r image.Rectangle, dy int) image.Rectangle {
r.Max.Y += dy
return r
}
func insetPt(r image.Rectangle, pad image.Point) image.Rectangle {
r.Min = r.Min.Add(pad)
r.Max = r.Max.Sub(pad)
return r
}
func outsetPt(r image.Rectangle, pad image.Point) image.Rectangle {
r.Min = r.Min.Sub(pad)
r.Max = r.Max.Add(pad)
return r
}
func minimum64(a, b int64) int64 {
if a < b {
return a
}
return b
}
func maximum64(a, b int64) int64 {
if a > b {
return a
}
return b
}
func minimum(a, b int) int {
if a < b {
return a
}
return b
}
func maximum(a, b int) int {
if a > b {
return a
}
return b
}
func debugLayout(d *duit.DUI, self *duit.Kid) {
if d.DebugLayout > 0 {
log.Printf("duit: Layout %T %s layout=%d draw=%d\n", self.UI, self.R, self.Layout, self.Draw)
}
}
func debugDraw(d *duit.DUI, self *duit.Kid) {
if d.DebugDraw > 0 {
log.Printf("duit: Draw %T %s layout=%d draw=%d\n", self.UI, self.R, self.Layout, self.Draw)
}
}
func duitError(d *duit.DUI, err error, msg string) bool {
if err == nil {
return false
}
go func() {
d.Error <- fmt.Errorf("%s: %s", msg, err)
}()
return true
}