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canvas.gui.ScrollArea: fix (wheel) scroll behavior.

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Rewrite the way scrolling for ScrollAreas is handled: Store
content position instead of scrollbar positions to keep position
on resize and promote moving the content instead of the contents
to as primary API.
Let the mousewheel scroll by fixed content offset instead of
scrollbar offset to make it actually usable (especially with
low scrolling distance).
This commit is contained in:
Thomas Geymayer 2014-06-26 00:30:33 +02:00
parent b7f0b09df4
commit 0338d82c55
2 changed files with 98 additions and 84 deletions
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28
Nasal/canvas/gui/styles/DefaultStyle.nas
View file

@ -317,14 +317,16 @@ DefaultStyle.widgets["scroll-area"] = {
me.horiz.reset();
if( model._max_scroll[0] > 1 )
# only show scroll bar if horizontally scrollable
me.horiz.moveTo(model._scroll_pos[0], model._size[1] - 2)
.horiz(model._size[0] - model._max_scroll[0]);
me.horiz.moveTo( model._scroller_offset[0] + model._scroller_pos[0],
model._size[1] - 2 )
.horiz(model._scroller_size[0]);
me.vert.reset();
if( model._max_scroll[1] > 1 )
# only show scroll bar if vertically scrollable
me.vert.moveTo(model._size[0] - 2, model._scroll_pos[1])
.vert(model._size[1] - model._max_scroll[1]);
me.vert.moveTo( model._size[0] - 2,
model._scroller_offset[1] + model._scroller_pos[1] )
.vert(model._scroller_size[1]);
me._bg.reset()
.rect(0, 0, model._size[0], model._size[1]);
@ -339,5 +341,23 @@ DefaultStyle.widgets["scroll-area"] = {
return el.createChild("path", "scroll-" ~ orient)
.set("stroke", "#f07845")
.set("stroke-width", 4);
},
# Calculate size and limits of scroller
#
# @param model
# @param dir 0 for horizontal, 1 for vertical
# @return [scroller_size, min_pos, max_pos]
_updateScrollMetrics: func(model, dir)
{
if( model._content_size[dir] <= model._size[dir] )
return;
model._scroller_size[dir] =
math.max(
12,
model._size[dir] * (model._size[dir] / model._content_size[dir])
);
model._scroller_offset[dir] = 0;
model._scroller_delta[dir] = model._size[dir] - model._scroller_size[dir];
}
};

152
Nasal/canvas/gui/widgets/ScrollArea.nas
View file

@ -4,9 +4,9 @@ gui.widgets.ScrollArea = {
var cfg = Config.new(cfg);
var m = gui.Widget.new(gui.widgets.ScrollArea);
m._focus_policy = m.NoFocus;
m._scroll_pos = [0,0];
m._content_pos = [0, 0];
m._scroller_pos = [0, 0];
m._max_scroll = [0, 0];
m._content_size = [0, 0];
m._layout = nil;
if( style != nil )
@ -49,73 +49,58 @@ gui.widgets.ScrollArea = {
if( me._layout != nil )
me._layout.setGeometry(me._layout.geometry());
},
# Move the scrollbars to the coordinates x,y (or as far as possible) and
# update.
# Move contents to the coordinates x,y (or as far as possible)
#
# @param x The x coordinate (positive is right)
# @param y The y coordinate (positive is down)
moveTo: func(x, y)
scrollTo: func(x, y)
{
var bb = me._updateBB();
me._scroll_pos[0] = math.max(0, math.min(x, me._max_scroll[0]));
me._scroll_pos[1] = math.max(0, math.min(y, me._max_scroll[1]));
me.update(bb);
},
# Move the scrollable area to the top-most position and update.
moveToTop: func()
{
me._scroll_pos[1] = 0;
me._content_pos[0] = x;
me._content_pos[1] = y;
me.update();
},
# Move the scrollable area to the bottom-most position and update.
moveToBottom: func()
# Move the scrollable area to the top-most position
scrollToTop: func me.scrollTo( me._content_pos[0], 0 ),
# Move the scrollable area to the bottom-most position
scrollToBottom: func me.scrollTo( me._content_pos[0], me._max_scroll[1] ),
# Move the scrollable area to the left-most position
scrollToLeft: func me.scrollTo( 0, me._content_pos[1] ),
# Move the scrollable area to the right-most position
scrollToRight: func me.scrollTo( me._max_scroll[0], me._content_pos[1] ),
# Move content by given delta
scrollBy: func(x, y)
{
var bb = me._updateBB();
me._scroll_pos[1] = me._max_scroll[1];
me.update(bb);
return me.scrollTo( me._content_pos[0] + x,
me._content_pos[1] + y );
},
# Move the scrollable area to the left-most position and update.
moveToLeft: func()
# Set horizontal scrollbar position
horizScrollBarTo: func(x)
{
me._scroll_pos[0] = 0;
if( me._scroller_delta[0] < 1 )
return me;
me.update();
me.scrollTo( me._max_scroll[0] * (x / me._scroller_delta[0]),
me._content_pos[1] );
},
# Move the scrollable area to the right-most position and update.
moveToRight: func()
# Set vertical scrollbar position
vertScrollBarTo: func(y)
{
var bb = me._updateBB();
if( me._scroller_delta[1] < 1 )
return me;
me._scroll_pos[0] = me._max_scroll[0];
me.update(bb);
me.scrollTo( me._content_pos[0],
me._max_scroll[1] * (y / me._scroller_delta[1]) );
},
# Get position of scrollable content
getContentPosition: func()
# Move horizontal scrollbar by given offset
horizScrollBarBy: func(dx)
{
var pos = [0, 0];
if( me._max_scroll[0] > 1 )
pos[0] = (me._scroll_pos[0] / me._max_scroll[0])
* (me._content_size[0] - me._size[0]);
if( me._max_scroll[1] > 1 )
pos[1] = (me._scroll_pos[1] / me._max_scroll[1])
* (me._content_size[1] - me._size[1]);
return pos;
me.horizScrollBarTo(me._scroller_pos[0] + dx);
},
# Move content to the given position
moveContentTo: func(x, y)
# Move vertical scrollbar by given offset
vertScrollBarBy: func(dy)
{
var scroll_x = x / (me._content_size[0] - me._size[0]) * me._max_scroll[0];
var scroll_y = y / (me._content_size[1] - me._size[1]) * me._max_scroll[1];
return me.moveTo(scroll_x, scroll_y);
me.vertScrollBarTo(me._scroller_pos[1] + dy);
},
# Update scroll bar and content area.
#
@ -125,9 +110,8 @@ gui.widgets.ScrollArea = {
if (bb == nil) bb = me._updateBB();
if (bb == nil) return me;
var pos = me.getContentPosition();
var offset = [ me._content_offset[0] - pos[0],
me._content_offset[1] - pos[1] ];
var offset = [ me._content_offset[0] - me._content_pos[0],
me._content_offset[1] - me._content_pos[1] ];
me.getContent().setTranslation(offset);
me._view.update(me);
@ -142,9 +126,8 @@ gui.widgets.ScrollArea = {
view.horiz.addEventListener("mousedown", func(e) me._dragStart(e));
view._root.addEventListener("mousedown", func(e)
{
var pos = me.getContentPosition();
me._drag_offsetX = pos[0] + e.clientX;
me._drag_offsetY = pos[1] + e.clientY;
me._drag_offsetX = me._content_pos[0] + e.clientX;
me._drag_offsetY = me._content_pos[1] + e.clientY;
});
view.vert.addEventListener
@ -155,7 +138,7 @@ gui.widgets.ScrollArea = {
if( !me._enabled )
return;
me.moveTo(me._scroll_pos[0], me._drag_offsetY + e.clientY);
me.vertScrollBarTo(me._drag_offsetY + e.clientY);
e.stopPropagation();
}
);
@ -167,7 +150,7 @@ gui.widgets.ScrollArea = {
if( !me._enabled )
return;
me.moveTo(me._drag_offsetX + e.clientX, me._scroll_pos[1]);
me.horizScrollBarTo(me._drag_offsetX + e.clientX);
e.stopPropagation();
}
);
@ -180,7 +163,7 @@ gui.widgets.ScrollArea = {
if( !me._enabled )
return;
me.moveContentTo( me._drag_offsetX - e.clientX,
me.scrollTo( me._drag_offsetX - e.clientX,
me._drag_offsetY - e.clientY );
e.stopPropagation();
}
@ -193,7 +176,7 @@ gui.widgets.ScrollArea = {
if( !me._enabled )
return;
me.moveTo(me._scroll_pos[0], me._scroll_pos[1] - e.deltaY);
me.scrollBy(0, 30 * -e.deltaY); # TODO make step size configurable
e.stopPropagation();
}
);
@ -202,8 +185,8 @@ gui.widgets.ScrollArea = {
},
_dragStart: func(e)
{
me._drag_offsetX = me._scroll_pos[0] - e.clientX;
me._drag_offsetY = me._scroll_pos[1] - e.clientY;
me._drag_offsetX = me._scroller_pos[0] - e.clientX;
me._drag_offsetY = me._scroller_pos[1] - e.clientY;
e.stopPropagation();
},
_updateBB: func()
@ -238,23 +221,34 @@ gui.widgets.ScrollArea = {
me._content_offset = [0, 0];
}
if( w > me._size[0] )
{
var scroller_size = math.max(12, me._size[0] * (me._size[0] / w));
me._max_scroll[0] = me._size[0] - scroller_size;
}
else
me._max_scroll[0] = 0;
me._max_scroll[0] = math.max(0, w - me._size[0]);
me._max_scroll[1] = math.max(0, h - me._size[1]);
me._content_size = [w, h];
if( h > me._size[1] )
{
var scroller_size = math.max(12, me._size[1] * (me._size[1] / h));
me._max_scroll[1] = me._size[1] - scroller_size;
}
else
me._max_scroll[1] = 0;
# keep position within limit and only integer (to prevent artifacts on text,
# lines, etc. not alligned with pixel grid)
me._content_pos[0] =
math.max(0, math.min( math.round(me._content_pos[0]), me._max_scroll[0]));
me._content_pos[1] =
math.max(0, math.min( math.round(me._content_pos[1]), me._max_scroll[1]));
me._content_size[0] = w;
me._content_size[1] = h;
me._scroller_size = [0, 0]; # scroller size
me._scroller_offset = [0, 0]; # scroller minimum pos (eg. add offset for
# scrolling with buttons)
me._scroller_delta = [0, 0]; # scroller max travel distance
# update scroller size/offset/max delta
me._view._updateScrollMetrics(me, 0);
me._view._updateScrollMetrics(me, 1);
# update current scrollbar positions
me._scroller_pos[0] =
me._max_scroll[0] > 0
? (me._content_pos[0] / me._max_scroll[0]) * me._scroller_delta[0]
: 0;
me._scroller_pos[1] =
me._max_scroll[1] > 0
? (me._content_pos[1] / me._max_scroll[1]) * me._scroller_delta[1]
: 0;
}
};