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Improve scroll-to-caret behaviour.

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This commit is contained in:
Michael Drake 2013-02-08 19:46:35 +00:00
parent 59d24187f7
commit 7a397d29c6
1 changed files with 58 additions and 39 deletions
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83
desktop/textarea.c
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@ -260,10 +260,10 @@ static bool textarea_select_fragment(struct textarea * ta)
static bool textarea_scroll_visible(struct textarea *ta)
{
int x0, x1, y0, y1; /* area we want caret inside */
int xc, yc; /* area centre */
int x, y; /* caret pos */
int xs = ta->scroll_x;
int ys = ta->scroll_y;
int vis;
bool scrolled = false;
if (ta->caret_pos.char_off == -1)
@ -271,26 +271,30 @@ static bool textarea_scroll_visible(struct textarea *ta)
x0 = ta->border_width + ta->pad_left;
x1 = ta->vis_width - (ta->border_width + ta->pad_right);
y0 = 0;
y1 = ta->vis_height - 2 * ta->border_width -
ta->pad_top - ta->pad_bottom;
xc = (x1 - x0) / 2 + x0;
yc = (y1 - y0) / 2 + y0;
/* Adjust scroll pos for reduced extents */
vis = ta->vis_width - 2 * ta->border_width;
if (ta->h_extent - xs < vis)
xs -= vis - (ta->h_extent - xs);
/* Get caret pos on screen */
x = ta->caret_x - xs;
y = ta->caret_y + ta->line_height / 2 - ys;
/* horizontal scroll; centre caret */
xs += x - xc;
/* scroll as required */
if (x < x0)
xs += (x - x0);
else if (x > x1)
xs += (x - x1);
/* force back into range */
if (xs < 0)
xs = 0;
else if (xs > ta->h_extent - (x1 - x0))
xs = ta->h_extent - (x1 - x0);
if (ta->bar_x == NULL && ta->scroll_x != 0 &&
ta->flags & TEXTAREA_MULTILINE) {
/* Scrollbar removed, set to zero */
ta->scroll_x = 0;
scrolled = true;
/* If scrolled, set new pos. */
if (xs != ta->scroll_x && ta->bar_x != NULL) {
} else if (xs != ta->scroll_x) {
/* Scrolled, set new pos. */
if (ta->bar_x != NULL) {
scrollbar_set(ta->bar_x, xs, false);
xs = scrollbar_get_offset(ta->bar_x);
if (xs != ta->scroll_x) {
@ -298,29 +302,35 @@ static bool textarea_scroll_visible(struct textarea *ta)
scrolled = true;
}
} else if (ta->flags & TEXTAREA_MULTILINE && ta->bar_x == NULL &&
ta->scroll_x != 0) {
ta->scroll_x = 0;
scrolled = true;
} else if (xs != ta->scroll_x && !(ta->flags & TEXTAREA_MULTILINE)) {
} else if (!(ta->flags & TEXTAREA_MULTILINE)) {
ta->scroll_x = xs;
scrolled = true;
}
}
/* check and change vertical scroll */
if (ta->flags & TEXTAREA_MULTILINE) {
/* vertical scroll; centre caret */
ys += y - yc;
y0 = 0;
y1 = ta->vis_height - 2 * ta->border_width -
ta->pad_top - ta->pad_bottom;
/* force back into range */
if (ys < 0)
ys = 0;
else if (ys > ta->v_extent - (y1 - y0))
ys = ta->v_extent - (y1 - y0);
/* Adjust scroll pos for reduced extents */
vis = ta->vis_height - 2 * ta->border_width;
if (ta->v_extent - xs < vis)
xs -= vis - (ta->v_extent - xs);
/* Get caret pos on screen */
y = ta->caret_y - ys;
/* scroll as required */
if (y < y0)
ys += (y - y0);
else if (y > y1)
ys += (y - y1);
/* If scrolled, set new pos. */
if (ys != ta->scroll_y && ta->bar_y != NULL) {
/* Scrolled, set new pos. */
scrollbar_set(ta->bar_y, ys, false);
ys = scrollbar_get_offset(ta->bar_y);
if (ys != ta->scroll_y) {
@ -329,6 +339,7 @@ static bool textarea_scroll_visible(struct textarea *ta)
}
} else if (ta->bar_y == NULL && ta->scroll_y != 0) {
/* Scrollbar removed, set to zero */
ta->scroll_y = 0;
scrolled = true;
}
@ -483,7 +494,7 @@ static bool textarea_reflow(struct textarea *ta, unsigned int start)
if (x > w)
w = x;
ta->h_extent = w + ta->pad_left - ta->pad_right;
ta->h_extent = w + ta->pad_left + ta->pad_right;
ta->line_count = 1;
return true;
@ -2074,7 +2085,8 @@ bool textarea_mouse_action(struct textarea *ta, browser_mouse_state mouse,
return textarea_select_fragment(ta);
}
} else if (mouse & (BROWSER_MOUSE_DRAG_1 | BROWSER_MOUSE_HOLDING_1)) {
} else if (mouse & BROWSER_MOUSE_DRAG_1) {
/* Selection start */
textarea_get_xy_offset(ta, x, y, &c_off);
c_start = ta->drag_start_char;
c_end = c_off;
@ -2086,6 +2098,13 @@ bool textarea_mouse_action(struct textarea *ta, browser_mouse_state mouse,
ta->callback(ta->data, &msg);
return textarea_select(ta, c_start, c_end);
} else if (mouse & BROWSER_MOUSE_HOLDING_1 &&
ta->drag_info.type == TEXTAREA_DRAG_SELECTION) {
/* Selection track */
textarea_get_xy_offset(ta, x, y, &c_off);
c_start = ta->drag_start_char;
c_end = c_off;
return textarea_select(ta, c_start, c_end);
}