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Add support for SDL2 MultiGestureEvents

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This commit is contained in:
Noah 2021-10-06 19:35:24 -07:00
parent a9231fc038
commit 09a6c1db52
7 changed files with 194 additions and 147 deletions
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18
README.md
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@ -135,6 +135,24 @@ for pt := range render.IterLine(A, B) {
* IterEllipse(A Point, B Point): draw an elipse fitting inside the
rectangle bounded by points A and B.
## Multitouch Gesture Notes
Support for SDL2's MultiGestureEvent is added on October 6 2021.
The event.State will have the property `Touching=true` while the engine
believes multitouch gestures are afoot. This begins when the user touches
the screen with two fingers, and _then_ motion is detected.
SDL2 spams us with gesture events for each tiny change detected, and then
just stops. The SDL driver in this repo doesn't set ev.State.Touching=false.
One heuristic you may use in your program to detect when multitouch has
ended is this:
SDL2 always emulates the mouse Button1 click for one of the fingers.
Record the position at the first Touching=true event, and monitor for
delta changes in position as the "mouse cursor" moves. When delta
movements become stale and don't update, you can set State.Touching=false
in your program.
## License
MIT.

24
color.go
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@ -19,6 +19,30 @@ var (
reHexColor8 = regexp.MustCompile(`^([A-Fa-f0-9]{2})([A-Fa-f0-9]{2})([A-Fa-f0-9]{2})([A-Fa-f0-9]{2})$`)
)
// Common color names.
var (
Invisible = Color{}
White = RGBA(255, 255, 255, 255)
Grey = RGBA(153, 153, 153, 255)
DarkGrey = RGBA(64, 64, 64, 255)
Black = RGBA(0, 0, 0, 255)
SkyBlue = RGBA(0, 153, 255, 255)
Blue = RGBA(0, 0, 255, 255)
DarkBlue = RGBA(0, 0, 153, 255)
Red = RGBA(255, 0, 0, 255)
DarkRed = RGBA(153, 0, 0, 255)
Green = RGBA(0, 255, 0, 255)
DarkGreen = RGBA(0, 153, 0, 255)
Cyan = RGBA(0, 255, 255, 255)
DarkCyan = RGBA(0, 153, 153, 255)
Yellow = RGBA(255, 255, 0, 255)
Orange = RGBA(255, 153, 0, 255)
DarkYellow = RGBA(153, 153, 0, 255)
Magenta = RGBA(255, 0, 255, 255)
Purple = RGBA(153, 0, 153, 255)
Pink = RGBA(255, 153, 255, 255)
)
// Color holds an RGBA color value.
type Color struct {
Red uint8

12
event/event.go
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@ -1,6 +1,8 @@
package event
import "strings"
import (
"strings"
)
// State holds the current state of key/mouse events.
type State struct {
@ -30,6 +32,14 @@ type State struct {
// Window resized
WindowResized bool
// Touch state
Touching bool
TouchNumFingers int
TouchCenterX int
TouchCenterY int
GestureRotated float64
GesturePinched float64
}
// NewState creates a new event.State.

146
interface.go
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@ -1,7 +1,6 @@
package render
import (
"fmt"
"image"
"git.kirsle.net/go/render/event"
@ -51,148 +50,3 @@ type Texturer interface {
Size() Rect
Image() image.Image
}
// Rect has a coordinate and a width and height.
type Rect struct {
X int
Y int
W int
H int
}
// NewRect creates a rectangle of size `width` and `height`. The X,Y values
// are initialized to zero.
func NewRect(width, height int) Rect {
return Rect{
W: width,
H: height,
}
}
func (r Rect) String() string {
return fmt.Sprintf("Rect<%d,%d,%d,%d>",
r.X, r.Y, r.W, r.H,
)
}
// Point returns the rectangle's X,Y values as a Point.
func (r Rect) Point() Point {
return Point{
X: r.X,
Y: r.Y,
}
}
// Bigger returns if the given rect is larger than the current one.
func (r Rect) Bigger(other Rect) bool {
// TODO: don't know why this is !
return !(other.X < r.X || // Lefter
other.Y < r.Y || // Higher
other.W > r.W || // Wider
other.H > r.H) // Taller
}
// Intersects with the other rectangle in any way.
func (r Rect) Intersects(other Rect) bool {
// Do a bidirectional compare.
compare := func(a, b Rect) bool {
var corners = []Point{
NewPoint(b.X, b.Y),
NewPoint(b.X, b.Y+b.H),
NewPoint(b.X+b.W, b.Y),
NewPoint(b.X+b.W, b.Y+b.H),
}
for _, pt := range corners {
if pt.Inside(a) {
return true
}
}
return false
}
return compare(r, other) || compare(other, r) || false
}
// IsZero returns if the Rect is uninitialized.
func (r Rect) IsZero() bool {
return r.X == 0 && r.Y == 0 && r.W == 0 && r.H == 0
}
// Add another rect.
func (r Rect) Add(other Rect) Rect {
return Rect{
X: r.X + other.X,
Y: r.Y + other.Y,
W: r.W + other.W,
H: r.H + other.H,
}
}
// Add a point to move the rect.
func (r Rect) AddPoint(other Point) Rect {
return Rect{
X: r.X + other.X,
Y: r.Y + other.Y,
W: r.W,
H: r.H,
}
}
// SubtractPoint is the inverse of AddPoint. Use this only if you need to invert
// the Point being added.
//
// This does r.X - other.X, r.Y - other.Y and keeps the width/height the same.
func (r Rect) SubtractPoint(other Point) Rect {
return Rect{
X: r.X - other.X,
Y: r.Y - other.Y,
W: r.W,
H: r.H,
}
}
// Text holds information for drawing text.
type Text struct {
Text string
Size int
Color Color
Padding int
PadX int
PadY int
Stroke Color // Stroke color (if not zero)
Shadow Color // Drop shadow color (if not zero)
FontFilename string // Path to *.ttf file on disk
}
func (t Text) String() string {
return fmt.Sprintf(`Text<"%s" %dpx %s>`, t.Text, t.Size, t.Color)
}
// IsZero returns if the Text is the zero value.
func (t Text) IsZero() bool {
return t.Text == "" && t.Size == 0 && t.Color == Invisible && t.Padding == 0 && t.PadX == 0 && t.PadY == 0 && t.Stroke == Invisible && t.Shadow == Invisible
}
// Common color names.
var (
Invisible = Color{}
White = RGBA(255, 255, 255, 255)
Grey = RGBA(153, 153, 153, 255)
DarkGrey = RGBA(64, 64, 64, 255)
Black = RGBA(0, 0, 0, 255)
SkyBlue = RGBA(0, 153, 255, 255)
Blue = RGBA(0, 0, 255, 255)
DarkBlue = RGBA(0, 0, 153, 255)
Red = RGBA(255, 0, 0, 255)
DarkRed = RGBA(153, 0, 0, 255)
Green = RGBA(0, 255, 0, 255)
DarkGreen = RGBA(0, 153, 0, 255)
Cyan = RGBA(0, 255, 255, 255)
DarkCyan = RGBA(0, 153, 153, 255)
Yellow = RGBA(255, 255, 0, 255)
Orange = RGBA(255, 153, 0, 255)
DarkYellow = RGBA(153, 153, 0, 255)
Magenta = RGBA(255, 0, 255, 255)
Purple = RGBA(153, 0, 153, 255)
Pink = RGBA(255, 153, 255, 255)
)

102
rect.go Normal file
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@ -0,0 +1,102 @@
package render
import "fmt"
// Rect has a coordinate and a width and height.
type Rect struct {
X int
Y int
W int
H int
}
// NewRect creates a rectangle of size `width` and `height`. The X,Y values
// are initialized to zero.
func NewRect(width, height int) Rect {
return Rect{
W: width,
H: height,
}
}
func (r Rect) String() string {
return fmt.Sprintf("Rect<%d,%d,%d,%d>",
r.X, r.Y, r.W, r.H,
)
}
// Point returns the rectangle's X,Y values as a Point.
func (r Rect) Point() Point {
return Point{
X: r.X,
Y: r.Y,
}
}
// Bigger returns if the given rect is larger than the current one.
func (r Rect) Bigger(other Rect) bool {
// TODO: don't know why this is !
return !(other.X < r.X || // Lefter
other.Y < r.Y || // Higher
other.W > r.W || // Wider
other.H > r.H) // Taller
}
// Intersects with the other rectangle in any way.
func (r Rect) Intersects(other Rect) bool {
// Do a bidirectional compare.
compare := func(a, b Rect) bool {
var corners = []Point{
NewPoint(b.X, b.Y),
NewPoint(b.X, b.Y+b.H),
NewPoint(b.X+b.W, b.Y),
NewPoint(b.X+b.W, b.Y+b.H),
}
for _, pt := range corners {
if pt.Inside(a) {
return true
}
}
return false
}
return compare(r, other) || compare(other, r) || false
}
// IsZero returns if the Rect is uninitialized.
func (r Rect) IsZero() bool {
return r.X == 0 && r.Y == 0 && r.W == 0 && r.H == 0
}
// Add another rect.
func (r Rect) Add(other Rect) Rect {
return Rect{
X: r.X + other.X,
Y: r.Y + other.Y,
W: r.W + other.W,
H: r.H + other.H,
}
}
// Add a point to move the rect.
func (r Rect) AddPoint(other Point) Rect {
return Rect{
X: r.X + other.X,
Y: r.Y + other.Y,
W: r.W,
H: r.H,
}
}
// SubtractPoint is the inverse of AddPoint. Use this only if you need to invert
// the Point being added.
//
// This does r.X - other.X, r.Y - other.Y and keeps the width/height the same.
func (r Rect) SubtractPoint(other Point) Rect {
return Rect{
X: r.X - other.X,
Y: r.Y - other.Y,
W: r.W,
H: r.H,
}
}

14
sdl/events.go
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@ -11,6 +11,7 @@ import (
// Debug certain SDL events
var (
DebugWindowEvents = false
DebugTouchEvents = false
DebugMouseEvents = false
DebugClickEvents = false
DebugKeyEvents = false
@ -22,6 +23,7 @@ func (r *Renderer) Poll() (*event.State, error) {
// Reset some events.
s.WindowResized = false
// s.Touching = false
// helper function to push keyboard key names on keyDown events only.
pushKey := func(name string, state uint8) {
@ -105,6 +107,18 @@ func (r *Renderer) Poll() (*event.State, error) {
t.Timestamp, r.ticks, t.Type, t.Which, t.X, t.Y,
)
}
case *sdl.MultiGestureEvent:
if DebugTouchEvents {
fmt.Printf("[%d ms] tick:%d MultiGesture type:%d Num=%d TouchID=%+v Dt=%f Dd=%f XY=%f,%f\n",
t.Timestamp, r.ticks, t.Type, t.NumFingers, t.TouchID, t.DTheta, t.DDist, t.X, t.Y,
)
}
s.Touching = true
s.TouchNumFingers = int(t.NumFingers)
s.TouchCenterX = int(t.X)
s.TouchCenterY = int(t.Y)
s.GesturePinched = float64(t.DDist)
s.GestureRotated = float64(t.DTheta)
case *sdl.KeyboardEvent:
if DebugKeyEvents {
fmt.Printf("[%d ms] tick:%d Keyboard type:%d sym:%c modifiers:%d state:%d repeat:%d\n",

25
text.go Normal file
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@ -0,0 +1,25 @@
package render
import "fmt"
// Text holds information for drawing text.
type Text struct {
Text string
Size int
Color Color
Padding int
PadX int
PadY int
Stroke Color // Stroke color (if not zero)
Shadow Color // Drop shadow color (if not zero)
FontFilename string // Path to *.ttf file on disk
}
func (t Text) String() string {
return fmt.Sprintf(`Text<"%s" %dpx %s>`, t.Text, t.Size, t.Color)
}
// IsZero returns if the Text is the zero value.
func (t Text) IsZero() bool {
return t.Text == "" && t.Size == 0 && t.Color == Invisible && t.Padding == 0 && t.PadX == 0 && t.PadY == 0 && t.Stroke == Invisible && t.Shadow == Invisible
}