mirror of https://github.com/kidoman/embd
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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