/**
* Modifies the passed-in token list to start at the specified offset. For example, if the token
* list covered positions 20-60 in the document (inclusive) like so:
*
* <pre>
* [token1] -> [token2] -> [token3] -> [token4]
* 20 30 31 40 41 50 51 60
* </pre>
*
* and you used this method to make the token list start at position 44, then the token list would
* be modified to be the following:
*
* <pre>
* [part-of-old-token3] -> [token4]
* 44 50 51 60
* </pre>
*
* Tokens that come before the specified position are forever lost, and the token containing that
* position is made to begin at that position if necessary. All token types remain the same as
* they were originally.
*
* <p>This method can be useful if you are only interested in part of a token list (i.e., the line
* it represents), but you don't want to modify the token list yourself.
*
* @param tokenList The list to make start at the specified position. This parameter is modified.
* @param pos The position at which the new token list is to start. If this position is not in the
* passed-in token list, returned token list will either be <code>null</code> or the
* unpaintable token(s) at the end of the passed-in token list.
* @param e How to expand tabs.
* @param textArea The text area from which the token list came.
* @param x0 The initial x-pixel position of the old token list.
* @return The width, in pixels, of the part of the token list "removed from the front." This way,
* you know the x-offset of the "new" token list.
*/
public static float makeTokenListStartAt(
Token tokenList, int pos, TabExpander e, final RSyntaxTextArea textArea, float x0) {
Token t = tokenList;
// Loop through the token list until you find the one that contains
// pos. Remember the cumulative width of all of these tokens.
while (t != null && t.isPaintable() && !t.containsPosition(pos)) {
x0 += t.getWidth(textArea, e, x0);
t = t.getNextToken();
}
// Make the token that contains pos start at pos.
if (t != null && t.isPaintable() && t.offset != pos) {
// Number of chars between p0 and token start.
int difference = pos - t.offset;
x0 += t.getWidthUpTo(t.textCount - difference + 1, textArea, e, x0);
t.makeStartAt(pos);
}
// Make the passed-in token list point to the proper place.
// t can be null, for example, if line ends with unended MLC.
if (t != null && t.isPaintable()) tokenList.copyFrom(t);
else tokenList = null;
t = null;
// Return the x-offset (in pixels) of the newly-modified t.
return x0;
}
/**
* Determines the width of the given token list taking tabs into consideration and only up to the
* given index in the document (exclusive).
*
* @param tokenList The token list representing the text.
* @param textArea The text area in which this token list resides.
* @param e The tab expander. This value cannot be <code>null</code>.
* @param x0 The x-pixel coordinate of the start of the token list.
* @param upTo The document position at which you want to stop, exclusive. If this position is
* before the starting position of the token list, a width of <code>0</code> will be returned;
* similarly, if this position comes after the entire token list, the width of the entire
* token list is returned.
* @return The width of the token list, in pixels, up to, but not including, the character at
* position <code>upTo</code>.
* @see #getTokenListWidth
*/
public static final float getTokenListWidthUpTo(
final Token tokenList, RSyntaxTextArea textArea, TabExpander e, float x0, int upTo) {
float width = 0;
for (Token t = tokenList; t != null && t.isPaintable(); t = t.getNextToken()) {
if (t.containsPosition(upTo)) {
return width + t.getWidthUpTo(upTo - t.offset, textArea, e, x0 + width);
}
width += t.getWidth(textArea, e, x0 + width);
}
return width;
}