140 lines
2.7 KiB
Go
140 lines
2.7 KiB
Go
// Editor methods involved in drawing to the console
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package editor
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import (
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"fmt"
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"strings"
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"timshome.page/gilo/terminal"
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)
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// ----------------------------------------------------------------------------
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// !Editor Methods
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// ----------------------------------------------------------------------------
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func (e *editor) RefreshScreen() {
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e.scroll()
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ab := newBuffer()
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ab.append(terminal.HideCursor)
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ab.append(terminal.ResetCursor)
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e.drawRows(ab)
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ab.append(terminal.MoveCursor(e.cursor.x - e.offset.x, e.cursor.y - e.offset.y))
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ab.append(terminal.ShowCursor)
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terminal.Write(ab.toString())
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}
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func (e *editor) scroll() {
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if e.cursor.y < e.offset.y {
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e.offset.y = e.cursor.y
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}
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if e.cursor.y >= e.offset.y + e.screen.Rows {
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e.offset.y = e.cursor.y - e.screen.Rows + 1
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}
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if e.cursor.x < e.offset.x {
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e.offset.x = e.cursor.x
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}
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if e.cursor.x >= e.offset.x + e.screen.Cols {
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e.offset.x = e.cursor.x - e.screen.Cols
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}
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}
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func (e *editor) drawRows(ab *buffer) {
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for y :=0; y < e.screen.Rows; y++ {
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fileRow := y + e.offset.y
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if fileRow >= len(e.rows) {
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e.drawPlaceholderRow(y, ab)
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} else {
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rawRow := e.rows[fileRow]
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// If the column offset is greater than the length of the row,
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// just display an empty row
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if e.offset.x > rawRow.size() {
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ab.append("")
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continue
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}
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rowLen := e.rows[fileRow].rSize() - e.offset.x
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outputRow := truncateString(string(e.rows[fileRow].render[e.offset.x:]), rowLen)
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ab.append(outputRow)
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}
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ab.append(terminal.ClearLine)
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if y < (e.screen.Rows - 1) {
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ab.append("\r\n")
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}
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}
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}
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func (e *editor) drawPlaceholderRow(y int, ab *buffer) {
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if len(e.rows) == 0 && y == e.screen.Rows / 3 {
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welcome := fmt.Sprintf("Gilo editor -- version %s", KiloVersion)
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if len(welcome) > e.screen.Cols {
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welcome = truncateString(welcome, e.screen.Cols)
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}
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padding := (e.screen.Cols - len(welcome)) / 2
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if padding > 0 {
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ab.appendRune('~')
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padding--
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}
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for padding > 0 {
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padding--
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ab.appendRune(' ')
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}
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ab.append(welcome)
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} else {
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ab.appendRune('~')
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}
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}
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// ----------------------------------------------------------------------------
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// !Output Buffer
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// ----------------------------------------------------------------------------
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type buffer struct {
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buf *strings.Builder
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}
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func newBuffer() *buffer {
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var buf strings.Builder
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b := new(buffer)
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b.buf = &buf
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return b
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}
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func (b *buffer) appendRune(r rune) int {
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size, _ := b.buf.WriteRune(r)
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return size
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}
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func (b *buffer) append(s string) int {
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size, _ := b.buf.WriteString(s)
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return size
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}
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func (b *buffer) appendLn(s string) int {
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str := fmt.Sprintf("%s\r\n", s)
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size, _ := b.buf.WriteString(str)
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return size
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}
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func (b *buffer) toString() string {
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return b.buf.String()
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} |