public MoveDetails CalculateNewPosition(MoveDetails moveDetails)
{
moveDetails.MoveIndex = moveIndex;
var newMoveDetails = Mover(moveDetails);
moveIndex = newMoveDetails.MoveIndex;
return(newMoveDetails);
}
public App()
{
// Sample text from Treasure Island (Stevenson, 1894).
var sampleText = "SQUIRE TRELAWNEY, Dr. Livesey, and the rest of these gentlemen having asked me to write down the whole particulars about Treasure Island, from the beginning to the end, keeping nothing back but the bearings of the island, and that only because there is still treasure not yet lifted, I take up my pen in the year of grace 17__ and go back to the time when my father kept the Admiral Benbow inn and the brown old seaman with the sabre cut first took up his lodging under our roof.";
Func <MoveDetails, MoveDetails> doSomeFunMoving = (moveDetails) => {
double moveDelta = (moveDetails.DeltaMovement.Height < 0 ? moveDetails.DeltaMovement.Height : 0.0); // currently only move for up panning
Point location;
float width = (float)moveDetails.CurrentBounds.Width;
SizeF remainingDelta;
Rectangle bounds;
while (moveDetails.DeltaMovement != SizeF.Empty)
{
bounds = moveDetails.CurrentBounds;
location = bounds.Location;
remainingDelta = moveDetails.DeltaMovement;
switch (moveDetails.MoveIndex)
{
case 0:
location.Y += moveDelta;
if (location.Y < 0)
{
// Overshot destination; put the rest back; move on.
remainingDelta.Height = (float)location.Y;
location.Y = 0;
moveDetails.MoveIndex += 1;
}
else
{
remainingDelta = SizeF.Empty;
}
break;
case 1:
var right = bounds.Right;
var left = bounds.Left;
var parentCenter = moveDetails.ParentBounds.Center.X;
bool moveLeft = right < parentCenter || (parentCenter - left > right - parentCenter);
if (moveLeft)
{
location.X += moveDelta;
}
else
{
location.X -= moveDelta;
}
if (location.X < 0 || location.X + width > moveDetails.ParentBounds.Right)
{
// Overshot destination; put the rest back; move on.
if (location.X < 0)
{
remainingDelta.Height = (float)location.X;
location.X = 0;
}
else
{
remainingDelta.Height = (float)moveDetails.ParentBounds.Right - width - (float)location.X;
location.X = moveDetails.ParentBounds.Right - width;
}
moveDetails.DeltaMovement = remainingDelta;
moveDetails.MoveIndex += 1;
}
else
{
remainingDelta = SizeF.Empty;
}
break;
case 2:
location.Y -= moveDelta;
if (location.Y > moveDetails.ParentBounds.Height)
{
// We're done now; zero out to stop loop.
remainingDelta = SizeF.Empty;
moveDetails.MoveIndex += 1;
}
else
{
remainingDelta = SizeF.Empty;
}
break;
default:
remainingDelta = SizeF.Empty;
break;
}
bounds.Location = location;
moveDetails.DeltaMovement = remainingDelta;
moveDetails.CurrentBounds = bounds;
}
return(moveDetails);
};
var wordLabels = sampleText.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).Select(word => new MovableLabel(doSomeFunMoving)
{
Text = word,
}).ToList();
funkyAbsoluteLayout = new AbsoluteLayout();
foreach (var wordLabel in wordLabels)
{
funkyAbsoluteLayout.Children.Add(wordLabel);
}
;
const double lineLeading = 3;
const double wordSpacing = 3;
funkyAbsoluteLayout.SizeChanged += (sender, e) => {
// Lay out a bunch of text manually, because YOLO and such.
double x = 0;
double y = 0;
foreach (var wordLabel in wordLabels)
{
if (x + wordLabel.Bounds.Width > funkyAbsoluteLayout.Width)
{
// NOTE: totally fails to wrap words longer than `funkyAbsoluteLayout.Width`.
y += wordLabel.Bounds.Height + lineLeading;
x = 0;
}
var newBounds = new Rectangle(new Point(x, y), wordLabel.Bounds.Size);
AbsoluteLayout.SetLayoutBounds(wordLabel, newBounds);
x = newBounds.Right + wordSpacing;
}
};
var touchesContentPage = new TouchesContentPage {
Content = funkyAbsoluteLayout,
Padding = new Thickness(5, Device.OnPlatform(iOS: 25, Android: 5, WinPhone: 5), 5, 5),
BackgroundColor = Color.Aqua,
};
touchesContentPage.OnPanned += (object sender, SizeF e) => {
// TODO: Parallel.ForEach?
var parentBoundsWithoutPadding = touchesContentPage.Bounds;
parentBoundsWithoutPadding.Height -= touchesContentPage.Padding.Bottom + touchesContentPage.Padding.Top;
parentBoundsWithoutPadding.Width -= touchesContentPage.Padding.Right + touchesContentPage.Padding.Left;
foreach (var wordLabel in wordLabels)
{
var moveDetails = new MoveDetails {
ParentBounds = parentBoundsWithoutPadding,
CurrentBounds = wordLabel.Bounds,
DeltaMovement = e,
};
var resultMoveDetails = wordLabel.CalculateNewPosition(moveDetails);
AbsoluteLayout.SetLayoutBounds(wordLabel, resultMoveDetails.CurrentBounds);
}
};
MainPage = touchesContentPage;
}