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)
68 c.lastVisualX = c.GetVisualX()
71 // Loc gets the cursor location in terms of character number instead
73 // It's just a simple wrapper of ToCharPos
74 func (c *Cursor) Loc() int {
75 return ToCharPos(c.x, c.y, c.v.buf)
78 // ResetSelection resets the user's selection
79 func (c *Cursor) ResetSelection() {
84 // HasSelection returns whether or not the user has selected anything
85 func (c *Cursor) HasSelection() bool {
86 return c.curSelection[0] != c.curSelection[1]
89 // DeleteSelection deletes the currently selected text
90 func (c *Cursor) DeleteSelection() {
91 if c.curSelection[0] > c.curSelection[1] {
92 c.v.eh.Remove(c.curSelection[1], c.curSelection[0])
93 c.SetLoc(c.curSelection[1])
95 c.v.eh.Remove(c.curSelection[0], c.curSelection[1])
96 c.SetLoc(c.curSelection[0])
100 // GetSelection returns the cursor's selection
101 func (c *Cursor) GetSelection() string {
102 if c.curSelection[0] > c.curSelection[1] {
103 return string([]rune(c.v.buf.text)[c.curSelection[1]:c.curSelection[0]])
105 return string([]rune(c.v.buf.text)[c.curSelection[0]:c.curSelection[1]])
108 // SelectLine selects the current line
109 func (c *Cursor) SelectLine() {
111 c.curSelection[0] = c.Loc()
113 if len(c.v.buf.lines)-1 > c.y {
114 c.curSelection[1] = c.Loc() + 1
116 c.curSelection[1] = c.Loc()
119 c.origSelection = c.curSelection
122 // AddLineToSelection adds the current line to the selection
123 func (c *Cursor) AddLineToSelection() {
126 if loc < c.origSelection[0] {
128 c.curSelection[0] = c.Loc()
129 c.curSelection[1] = c.origSelection[1]
131 if loc > c.origSelection[1] {
133 c.curSelection[1] = c.Loc()
134 c.curSelection[0] = c.origSelection[0]
137 if loc < c.origSelection[1] && loc > c.origSelection[0] {
138 c.curSelection = c.origSelection
142 // SelectWord selects the word the cursor is currently on
143 func (c *Cursor) SelectWord() {
144 if len(c.v.buf.lines[c.y]) == 0 {
148 if !IsWordChar(string(c.RuneUnder(c.x))) {
150 c.curSelection[0] = loc
151 c.curSelection[1] = loc + 1
152 c.origSelection = c.curSelection
156 forward, backward := c.x, c.x
158 for backward > 0 && IsWordChar(string(c.RuneUnder(backward-1))) {
162 c.curSelection[0] = ToCharPos(backward, c.y, c.v.buf)
163 c.origSelection[0] = c.curSelection[0]
165 for forward < Count(c.v.buf.lines[c.y])-1 && IsWordChar(string(c.RuneUnder(forward+1))) {
169 c.curSelection[1] = ToCharPos(forward, c.y, c.v.buf) + 1
170 c.origSelection[1] = c.curSelection[1]
173 // AddWordToSelection adds the word the cursor is currently on to the selection
174 func (c *Cursor) AddWordToSelection() {
177 if loc > c.origSelection[0] && loc < c.origSelection[1] {
178 c.curSelection = c.origSelection
182 if loc < c.origSelection[0] {
185 for backward > 0 && IsWordChar(string(c.RuneUnder(backward-1))) {
189 c.curSelection[0] = ToCharPos(backward, c.y, c.v.buf)
190 c.curSelection[1] = c.origSelection[1]
193 if loc > c.origSelection[1] {
196 for forward < Count(c.v.buf.lines[c.y])-1 && IsWordChar(string(c.RuneUnder(forward+1))) {
200 c.curSelection[1] = ToCharPos(forward, c.y, c.v.buf) + 1
201 c.curSelection[0] = c.origSelection[0]
205 // RuneUnder returns the rune under the given x position
206 func (c *Cursor) RuneUnder(x int) rune {
207 line := []rune(c.v.buf.lines[c.y])
216 // Up moves the cursor up one line (if possible)
217 func (c *Cursor) Up() {
221 runes := []rune(c.v.buf.lines[c.y])
222 c.x = c.GetCharPosInLine(c.y, c.lastVisualX)
223 if c.x > len(runes) {
229 // Down moves the cursor down one line (if possible)
230 func (c *Cursor) Down() {
231 if c.y < len(c.v.buf.lines)-1 {
234 runes := []rune(c.v.buf.lines[c.y])
235 c.x = c.GetCharPosInLine(c.y, c.lastVisualX)
236 if c.x > len(runes) {
242 // Left moves the cursor left one cell (if possible) or to the last line if it is at the beginning
243 func (c *Cursor) Left() {
253 c.lastVisualX = c.GetVisualX()
256 // Right moves the cursor right one cell (if possible) or to the next line if it is at the end
257 func (c *Cursor) Right() {
258 if c.Loc() == c.v.buf.Len() {
261 if c.x < Count(c.v.buf.lines[c.y]) {
267 c.lastVisualX = c.GetVisualX()
270 // End moves the cursor to the end of the line it is on
271 func (c *Cursor) End() {
272 c.x = Count(c.v.buf.lines[c.y])
273 c.lastVisualX = c.GetVisualX()
276 // Start moves the cursor to the start of the line it is on
277 func (c *Cursor) Start() {
279 c.lastVisualX = c.GetVisualX()
282 // GetCharPosInLine gets the char position of a visual x y coordinate (this is necessary because tabs are 1 char but 4 visual spaces)
283 func (c *Cursor) GetCharPosInLine(lineNum, visualPos int) int {
285 tabSize := settings.TabSize
286 // This is the visual line -- every \t replaced with the correct number of spaces
287 visualLine := strings.Replace(c.v.buf.lines[lineNum], "\t", "\t"+Spaces(tabSize-1), -1)
288 if visualPos > Count(visualLine) {
289 visualPos = Count(visualLine)
291 numTabs := NumOccurences(visualLine[:visualPos], '\t')
292 if visualPos >= (tabSize-1)*numTabs {
293 return visualPos - (tabSize-1)*numTabs
295 return visualPos / tabSize
298 // GetVisualX returns the x value of the cursor in visual spaces
299 func (c *Cursor) GetVisualX() int {
300 runes := []rune(c.v.buf.lines[c.y])
301 tabSize := settings.TabSize
302 return c.x + NumOccurences(string(runes[:c.x]), '\t')*(tabSize-1)
305 // Display draws the cursor to the screen at the correct position
306 func (c *Cursor) Display() {
307 // Don't draw the cursor if it is out of the viewport or if it has a selection
308 if (c.y-c.v.topline < 0 || c.y-c.v.topline > c.v.height-1) || c.HasSelection() {
311 screen.ShowCursor(c.GetVisualX()+c.v.lineNumOffset-c.v.leftCol, c.y-c.v.topline)