103 lines
2.4 KiB
Go
103 lines
2.4 KiB
Go
// 11 february 2014
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package ui
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const eventbufsiz = 100 // suggested by skelterjohn
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// newEvent returns a new channel suitable for listening for events.
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func newEvent() chan struct{} {
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return make(chan struct{}, eventbufsiz)
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}
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// The sysData type contains all system data. It provides the system-specific underlying implementation. It is guaranteed to have the following by embedding:
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type cSysData struct {
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ctype int
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event chan struct{}
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resize func(x int, y int, width int, height int, rr *[]resizerequest)
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resizes []resizerequest
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alternate bool // editable for Combobox, multi-select for listbox, password for lineedit
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handler AreaHandler // for Areas
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}
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// this interface is used to make sure all sysDatas are synced
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var _xSysData interface {
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make(window *sysData) error
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firstShow() error
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show()
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hide()
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setText(text string)
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setRect(x int, y int, width int, height int, winheight int) error
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isChecked() bool
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text() string
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append(string)
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insertBefore(string, int)
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selectedIndex() int
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selectedIndices() []int
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selectedTexts() []string
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setWindowSize(int, int) error
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delete(int)
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preferredSize() (int, int)
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setProgress(int)
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len() int
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setAreaSize(int, int)
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} = &sysData{} // this line will error if there's an inconsistency
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// signal sends the event signal. This raise is done asynchronously to avoid deadlocking the UI task.
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// Thanks skelterjohn for this techinque: if we can't queue any more events, drop them
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func (s *cSysData) signal() {
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if s.event != nil {
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go func() {
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select {
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case s.event <- struct{}{}:
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default:
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}
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}()
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}
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}
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const (
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c_window = iota
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c_button
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c_checkbox
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c_combobox
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c_lineedit
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c_label
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c_listbox
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c_progressbar
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c_area
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nctypes
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)
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func mksysdata(ctype int) *sysData {
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s := &sysData{
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cSysData: cSysData{
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ctype: ctype,
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},
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}
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if ctype == c_window { // make resizes non-nil so it can be passed in
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s.resizes = make([]resizerequest, 0, 0)
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}
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return s
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}
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type resizerequest struct {
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sysData *sysData
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x int
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y int
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width int
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height int
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}
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func (s *sysData) doResize(x int, y int, width int, height int, winheight int) {
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if s.resize != nil {
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s.resizes = s.resizes[0:0] // set len to 0 without changing cap
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s.resize(x, y, width, height, &s.resizes)
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for _, s := range s.resizes {
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err := s.sysData.setRect(s.x, s.y, s.width, s.height, winheight)
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if err != nil {
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panic("child resize failed: " + err.Error())
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}
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}
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}
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}
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