doodle/pkg/uix/canvas_strokes.go
Noah Petherbridge cc1e441232 Eraser Tool, Brush Sizes
* Implement Brush Sizes for drawtool.Stroke and add a UI to the tools panel
  to control the brush size.
  * Brush sizes: 1, 2, 4, 8, 16, 24, 32, 48, 64
* Add the Eraser Tool to editor mode. It uses a default brush size of 16
  and a max size of 32 due to some performance issues.
* The Undo/Redo system now remembers the original color of pixels when
  you change them, so that Undo will set them back how they were instead
  of deleting the pixel entirely. Due to performance issues, this only
  happens when your Brush Size is 0 (drawing single-pixel shapes).
* UI: Add an IntVariable option to ui.Label to bind showing the value of
  an int reference.

Aforementioned performance issues:

* When we try to remember whole rects of pixels for drawing thick
  shapes, it requires a ton of scanning for each step of the shape. Even
  de-duplicating pixel checks, tons of extra reads are constantly
  checked.
* The Eraser is the only tool that absolutely needs to be able to
  remember wiped pixels AND have large brush sizes. The performance
  sucks and lags a bit if you erase a lot all at once, but it's a
  trade-off for now.
* So pixels aren't remembered when drawing lines in your level with
  thick brushes, so the Undo action will simply delete your pixels and not
  reset them. Only the Eraser can bring back pixels.
2019-07-11 19:07:46 -07:00

290 lines
7.9 KiB
Go

package uix
import (
"git.kirsle.net/apps/doodle/lib/render"
"git.kirsle.net/apps/doodle/lib/ui"
"git.kirsle.net/apps/doodle/pkg/balance"
"git.kirsle.net/apps/doodle/pkg/drawtool"
"git.kirsle.net/apps/doodle/pkg/level"
"git.kirsle.net/apps/doodle/pkg/log"
"git.kirsle.net/apps/doodle/pkg/shmem"
)
// canvas_strokes.go: functions related to drawtool.Stroke and the Canvas.
// AddStroke installs a new Stroke to be superimposed over drawing data
// in the canvas.
//
// The stroke is added to the canvas's map by its ID so it can be removed later.
// The stroke must have a non-zero ID value set or this function will panic.
// drawtool.NewStroke() creates an initialized Stroke object to use here.
func (w *Canvas) AddStroke(stroke *drawtool.Stroke) {
if stroke.ID == 0 {
panic("Canvas.AddStroke: the Stroke is missing an ID; was it initialized properly?")
}
w.strokes[stroke.ID] = stroke
}
// RemoveStroke uninstalls a Stroke from the canvas using its ID.
//
// Returns true if the stroke existed to begin with, false if not.
func (w *Canvas) RemoveStroke(stroke *drawtool.Stroke) bool {
if _, ok := w.strokes[stroke.ID]; ok {
delete(w.strokes, stroke.ID)
return true
}
return false
}
// UndoStroke rolls back the level's UndoHistory and deletes the pixels last
// added to the level. Returns false and emits a warning to the log if the
// canvas has no level loaded properly.
func (w *Canvas) UndoStroke() bool {
if w.level == nil {
log.Error("Canvas.UndoStroke: no Level currently available to the canvas")
return false
}
latest := w.level.UndoHistory.Latest()
if latest != nil {
// TODO: only single-thickness lines will restore the original color;
// thick lines just delete their pixels from the world due to performance.
// But the Eraser Tool is always thick, which always should restore its
// pixels. Can't do anything about that, so the inefficient thick rect
// restore is used only for Eraser at least.
if latest.Thickness > 0 {
if latest.Shape == drawtool.Eraser {
for rect := range latest.IterThickPoints() {
var (
xMin = rect.X
xMax = rect.X + rect.W
yMin = rect.Y
yMax = rect.Y + rect.H
)
for x := xMin; x < xMax; x++ {
for y := yMin; y < yMax; y++ {
if v, ok := latest.OriginalPoints[render.NewPoint(x, y)]; ok {
if swatch, ok := v.(*level.Swatch); ok {
w.chunks.Set(render.NewPoint(x, y), swatch)
}
}
}
}
}
} else {
for rect := range latest.IterThickPoints() {
w.chunks.DeleteRect(rect)
}
}
} else {
for point := range latest.IterPoints() {
// Was there a previous swatch at this point to restore?
if v, ok := latest.OriginalPoints[point]; ok {
if swatch, ok := v.(*level.Swatch); ok {
w.chunks.Set(point, swatch)
continue
}
}
w.chunks.Delete(point)
}
}
}
return w.level.UndoHistory.Undo()
}
// RedoStroke rolls the level's UndoHistory forwards again and replays the
// recently undone changes.
func (w *Canvas) RedoStroke() bool {
if w.level == nil {
log.Error("Canvas.UndoStroke: no Level currently available to the canvas")
return false
}
ok := w.level.UndoHistory.Redo()
if !ok {
return false
}
latest := w.level.UndoHistory.Latest()
// We stored the ActiveSwatch on this stroke as we drew it. Recover it
// and place the pixels back down.
w.currentStroke = latest
w.commitStroke(w.Tool, false)
return ok
}
// presentStrokes is called as part of Present() and draws the strokes whose
// pixels are currently visible within the viewport.
func (w *Canvas) presentStrokes(e render.Engine) {
// Turn stroke map into a list.
var strokes []*drawtool.Stroke
for _, stroke := range w.strokes {
strokes = append(strokes, stroke)
}
w.drawStrokes(e, strokes)
// Dynamic actor links visible in the ActorTool and LinkTool.
if w.Tool == drawtool.ActorTool || w.Tool == drawtool.LinkTool {
w.presentActorLinks(e)
}
}
// presentActorLinks draws strokes connecting actors together by their links.
// TODO: the strokes are computed dynamically every tick in here, might be a
// way to better optimize later.
func (w *Canvas) presentActorLinks(e render.Engine) {
var (
strokes = []*drawtool.Stroke{}
actorMap = map[string]*Actor{}
)
// Loop over actors and collect linked ones into the map.
for _, actor := range w.actors {
if len(actor.Actor.Links) > 0 {
actorMap[actor.ID()] = actor
}
}
// If no links, stop.
if len(actorMap) == 0 {
return
}
// The glow colored line. Huge hacky block of code but makes for some
// basic visualization for now.
var color = balance.LinkLineColor
var lightenStep = float64(balance.LinkLighten) / 16
var step = shmem.Tick % balance.LinkAnimSpeed
if step < 32 {
for i := uint64(0); i < step; i++ {
color = color.Lighten(int(lightenStep))
}
if step > 16 {
for i := uint64(0); i < step-16; i++ {
color = color.Darken(int(lightenStep))
}
}
}
// Loop over the linked actors and draw stroke lines.
for _, actor := range actorMap {
for _, linkID := range actor.Actor.Links {
if _, ok := actorMap[linkID]; !ok {
continue
}
var (
aP = actor.Position()
aS = actor.Size()
bP = actorMap[linkID].Position()
bS = actorMap[linkID].Size()
)
// Draw a line connecting the centers of each actor together.
stroke := drawtool.NewStroke(drawtool.Line, color)
stroke.Thickness = 1
stroke.PointA = render.Point{
X: aP.X + (aS.W / 2),
Y: aP.Y + (aS.H / 2),
}
stroke.PointB = render.Point{
X: bP.X + (bS.W / 2),
Y: bP.Y + (bS.H / 2),
}
strokes = append(strokes, stroke)
}
}
w.drawStrokes(e, strokes)
}
// drawStrokes is the common base function behind presentStrokes and
// presentActorLinks to actually draw the lines to the canvas.
func (w *Canvas) drawStrokes(e render.Engine, strokes []*drawtool.Stroke) {
var (
P = ui.AbsolutePosition(w) // Canvas point in UI
VP = w.ViewportRelative() // Canvas scroll viewport
)
for _, stroke := range strokes {
// If none of this stroke is in our viewport, don't waste time
// looping through it.
if stroke.Shape == drawtool.Freehand || stroke.Shape == drawtool.Eraser {
if len(stroke.Points) >= 2 {
if !stroke.Points[0].Inside(VP) && !stroke.Points[len(stroke.Points)-1].Inside(VP) {
continue
}
}
} else {
// TODO: a very long line that starts and ends outside the viewport
// but passes thru it would disappear when both ends are out of
// view.
if !stroke.PointA.Inside(VP) && !stroke.PointB.Inside(VP) {
continue
}
}
// Iter the points and draw what's visible.
if stroke.Thickness > 0 {
for rect := range stroke.IterThickPoints() {
if !rect.Intersects(VP) {
continue
}
// Destination rectangle to draw to screen, taking into account
// the position of the Canvas itself.
dest := render.Rect{
X: rect.X + P.X + w.Scroll.X + w.BoxThickness(1),
Y: rect.Y + P.Y + w.Scroll.Y + w.BoxThickness(1),
W: rect.W,
H: rect.H,
}
// Cap the render square so it doesn't leave the Canvas and
// overlap other UI elements!
if dest.X < P.X {
// Left edge. TODO: right edge
delta := P.X - dest.X
dest.X = P.X
dest.W -= delta
}
if dest.Y < P.Y {
// Top edge. TODO: bottom edge
delta := P.Y - dest.Y
dest.Y = P.Y
dest.H -= delta
}
if balance.DebugCanvasStrokeColor != render.Invisible {
e.DrawBox(balance.DebugCanvasStrokeColor, dest)
} else {
e.DrawBox(stroke.Color, dest)
}
}
} else {
for point := range stroke.IterPoints() {
if !point.Inside(VP) {
continue
}
dest := render.Point{
X: P.X + w.Scroll.X + w.BoxThickness(1) + point.X,
Y: P.Y + w.Scroll.Y + w.BoxThickness(1) + point.Y,
}
if balance.DebugCanvasStrokeColor != render.Invisible {
e.DrawPoint(balance.DebugCanvasStrokeColor, dest)
} else {
e.DrawPoint(stroke.Color, dest)
}
}
}
}
}