7 // FromCharPos converts from a character position to an x, y position
8 func FromCharPos(loc int, buf *Buffer) (int, int) {
9 return FromCharPosStart(0, 0, 0, loc, buf)
12 // FromCharPosStart converts from a character position to an x, y position, starting at the specified character location
13 func FromCharPosStart(startLoc, startX, startY, loc int, buf *Buffer) (int, int) {
15 x, y := startX, startY
17 lineLen := Count(buf.lines[y]) + 1
18 for charNum+lineLen <= loc {
21 lineLen = Count(buf.lines[y]) + 1
28 // ToCharPos converts from an x, y position to a character position
29 func ToCharPos(x, y int, buf *Buffer) int {
31 for i := 0; i < y; i++ {
32 // + 1 for the newline
33 loc += Count(buf.lines[i]) + 1
39 // The Cursor struct stores the location of the cursor in the view
40 // The complicated part about the cursor is storing its location.
41 // The cursor must be displayed at an x, y location, but since the buffer
42 // uses a rope to store text, to insert text we must have an index. It
43 // is also simpler to use character indicies for other tasks such as
48 // The cursor display location
52 // Last cursor x position
55 // The current selection as a range of character numbers (inclusive)
57 // The original selection as a range of character numbers
58 // This is used for line and word selection where it is necessary
59 // to know what the original selection was
63 // SetLoc sets the location of the cursor in terms of character number
64 // and not x, y location
65 // It's just a simple wrapper of FromCharPos
66 func (c *Cursor) SetLoc(loc int) {
67 c.x, c.y = FromCharPos(loc, c.v.buf)
70 // Loc gets the cursor location in terms of character number instead
72 // It's just a simple wrapper of ToCharPos
73 func (c *Cursor) Loc() int {
74 return ToCharPos(c.x, c.y, c.v.buf)
77 // ResetSelection resets the user's selection
78 func (c *Cursor) ResetSelection() {
83 // HasSelection returns whether or not the user has selected anything
84 func (c *Cursor) HasSelection() bool {
85 return c.curSelection[0] != c.curSelection[1]
88 // DeleteSelection deletes the currently selected text
89 func (c *Cursor) DeleteSelection() {
90 if c.curSelection[0] > c.curSelection[1] {
91 c.v.eh.Remove(c.curSelection[1], c.curSelection[0])
92 c.SetLoc(c.curSelection[1])
94 c.v.eh.Remove(c.curSelection[0], c.curSelection[1])
95 c.SetLoc(c.curSelection[0])
99 // GetSelection returns the cursor's selection
100 func (c *Cursor) GetSelection() string {
101 if c.curSelection[0] > c.curSelection[1] {
102 return string([]rune(c.v.buf.text)[c.curSelection[1]:c.curSelection[0]])
104 return string([]rune(c.v.buf.text)[c.curSelection[0]:c.curSelection[1]])
107 // SelectLine selects the current line
108 func (c *Cursor) SelectLine() {
110 c.curSelection[0] = c.Loc()
112 c.curSelection[1] = c.Loc()
114 c.origSelection = c.curSelection
117 // AddLineToSelection adds the current line to the selection
118 func (c *Cursor) AddLineToSelection() {
121 if loc < c.origSelection[0] {
123 c.curSelection[0] = c.Loc()
124 c.curSelection[1] = c.origSelection[1]
126 if loc > c.origSelection[1] {
128 c.curSelection[1] = c.Loc()
129 c.curSelection[0] = c.origSelection[0]
132 if loc < c.origSelection[1] && loc > c.origSelection[0] {
133 c.curSelection = c.origSelection
137 // SelectWord selects the word the cursor is currently on
138 func (c *Cursor) SelectWord() {
139 if len(c.v.buf.lines[c.y]) == 0 {
143 if !IsWordChar(string(c.RuneUnder(c.x))) {
145 c.curSelection[0] = loc
146 c.curSelection[1] = loc + 1
147 c.origSelection = c.curSelection
151 forward, backward := c.x, c.x
153 for backward > 0 && IsWordChar(string(c.RuneUnder(backward-1))) {
157 c.curSelection[0] = ToCharPos(backward, c.y, c.v.buf)
158 c.origSelection[0] = c.curSelection[0]
160 for forward < Count(c.v.buf.lines[c.y])-1 && IsWordChar(string(c.RuneUnder(forward+1))) {
164 c.curSelection[1] = ToCharPos(forward, c.y, c.v.buf) + 1
165 c.origSelection[1] = c.curSelection[1]
168 // AddWordToSelection adds the word the cursor is currently on to the selection
169 func (c *Cursor) AddWordToSelection() {
172 if loc > c.origSelection[0] && loc < c.origSelection[1] {
173 c.curSelection = c.origSelection
177 if loc < c.origSelection[0] {
180 for backward > 0 && IsWordChar(string(c.RuneUnder(backward-1))) {
184 c.curSelection[0] = ToCharPos(backward, c.y, c.v.buf)
185 c.curSelection[1] = c.origSelection[1]
188 if loc > c.origSelection[1] {
191 for forward < Count(c.v.buf.lines[c.y])-1 && IsWordChar(string(c.RuneUnder(forward+1))) {
195 c.curSelection[1] = ToCharPos(forward, c.y, c.v.buf) + 1
196 c.curSelection[0] = c.origSelection[0]
200 // RuneUnder returns the rune under the given x position
201 func (c *Cursor) RuneUnder(x int) rune {
202 line := []rune(c.v.buf.lines[c.y])
211 // Up moves the cursor up one line (if possible)
212 func (c *Cursor) Up() {
216 runes := []rune(c.v.buf.lines[c.y])
217 c.x = c.GetCharPosInLine(c.y, c.lastVisualX)
218 if c.x > len(runes) {
224 // Down moves the cursor down one line (if possible)
225 func (c *Cursor) Down() {
226 if c.y < len(c.v.buf.lines)-1 {
229 runes := []rune(c.v.buf.lines[c.y])
230 c.x = c.GetCharPosInLine(c.y, c.lastVisualX)
231 if c.x > len(runes) {
237 // Left moves the cursor left one cell (if possible) or to the last line if it is at the beginning
238 func (c *Cursor) Left() {
248 c.lastVisualX = c.GetVisualX()
251 // Right moves the cursor right one cell (if possible) or to the next line if it is at the end
252 func (c *Cursor) Right() {
253 if c.Loc() == c.v.buf.Len() {
256 if c.x < Count(c.v.buf.lines[c.y]) {
262 c.lastVisualX = c.GetVisualX()
265 // End moves the cursor to the end of the line it is on
266 func (c *Cursor) End() {
267 c.x = Count(c.v.buf.lines[c.y])
268 c.lastVisualX = c.GetVisualX()
271 // Start moves the cursor to the start of the line it is on
272 func (c *Cursor) Start() {
274 c.lastVisualX = c.GetVisualX()
277 // GetCharPosInLine gets the char position of a visual x y coordinate (this is necessary because tabs are 1 char but 4 visual spaces)
278 func (c *Cursor) GetCharPosInLine(lineNum, visualPos int) int {
280 tabSize := settings.TabSize
281 // This is the visual line -- every \t replaced with the correct number of spaces
282 visualLine := strings.Replace(c.v.buf.lines[lineNum], "\t", "\t"+Spaces(tabSize-1), -1)
283 if visualPos > Count(visualLine) {
284 visualPos = Count(visualLine)
286 numTabs := NumOccurences(visualLine[:visualPos], '\t')
287 if visualPos >= (tabSize-1)*numTabs {
288 return visualPos - (tabSize-1)*numTabs
290 return visualPos / tabSize
293 // GetVisualX returns the x value of the cursor in visual spaces
294 func (c *Cursor) GetVisualX() int {
295 runes := []rune(c.v.buf.lines[c.y])
296 tabSize := settings.TabSize
297 return c.x + NumOccurences(string(runes[:c.x]), '\t')*(tabSize-1)
300 // Display draws the cursor to the screen at the correct position
301 func (c *Cursor) Display() {
302 // Don't draw the cursor if it is out of the viewport or if it has a selection
303 if (c.y-c.v.topline < 0 || c.y-c.v.topline > c.v.height-1) || c.HasSelection() {
306 screen.ShowCursor(c.GetVisualX()+c.v.lineNumOffset-c.v.leftCol, c.y-c.v.topline)