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https://github.com/kidoman/embd
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915b3b76a7
the characterdisplay package is an abstraction layer for controlling character displays also includes refactors to the hd44780 package to fit the characterdisplay Controller interface
107 lines
3.1 KiB
Go
107 lines
3.1 KiB
Go
/*
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Package characterdisplay provides an ease-of-use layer on top of a character
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display controller.
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*/
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package characterdisplay
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// Controller is an interface that describes the basic functionality of a character
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// display controller.
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type Controller interface {
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DisplayOff() error // turns the display off
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DisplayOn() error // turns the display on
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CursorOff() error // sets the cursor visibility to off
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CursorOn() error // sets the cursor visibility to on
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BlinkOff() error // sets the cursor blink off
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BlinkOn() error // sets the cursor blink on
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ShiftLeft() error // moves the cursor and text one column to the left
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ShiftRight() error // moves the cursor and text one column to the right
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BacklightOff() error // turns the display backlight off
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BacklightOn() error // turns the display backlight on
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Home() error // moves the cursor to the home position
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Clear() error // clears the display and moves the cursor to the home position
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WriteChar(byte) error // writes a character to the display
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SetCursor(col, row int) error // sets the cursor position
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Close() error // closes the controller resources
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}
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// Display represents an abstract character display and provides a
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// ease-of-use layer on top of a character display controller.
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type Display struct {
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Controller
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cols, rows int
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p *position
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}
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type position struct {
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col int
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row int
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}
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// New creates a new Display
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func New(controller Controller, cols, rows int) *Display {
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return &Display{
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Controller: controller,
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cols: cols,
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rows: rows,
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p: &position{0, 0},
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}
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}
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// Home moves the cursor and all characters to the home position.
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func (disp *Display) Home() error {
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disp.setCurrentPosition(0, 0)
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return disp.Controller.Home()
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}
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// Clear clears the display, preserving the mode settings and setting the correct home.
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func (disp *Display) Clear() error {
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disp.setCurrentPosition(0, 0)
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return disp.Controller.Clear()
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}
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// Message prints the given string on the display, including interpreting newline
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// characters and wrapping at the end of lines.
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func (disp *Display) Message(message string) error {
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bytes := []byte(message)
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for _, b := range bytes {
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if b == byte('\n') {
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err := disp.Newline()
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if err != nil {
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return err
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}
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continue
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}
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err := disp.WriteChar(b)
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if err != nil {
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return err
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}
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disp.p.col++
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if disp.p.col >= disp.cols || disp.p.col < 0 {
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err := disp.Newline()
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if err != nil {
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return err
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}
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}
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}
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return nil
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}
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// Newline moves the input cursor to the beginning of the next line.
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func (disp *Display) Newline() error {
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return disp.SetCursor(0, disp.p.row+1)
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}
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// SetCursor sets the input cursor to the given position.
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func (disp *Display) SetCursor(col, row int) error {
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if row >= disp.rows {
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row = disp.rows - 1
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}
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disp.setCurrentPosition(col, row)
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return disp.Controller.SetCursor(col, row)
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}
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func (disp *Display) setCurrentPosition(col, row int) {
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disp.p.col = col
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disp.p.row = row
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}
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