/// <summary>
/// Creates a transformation matrix that can be used to transform the user-specific
/// to device units.
/// </summary>
/// <param name="deviceWidth">The device width, in device units.</param>
/// <param name="deviceHeight">The device height, in device units.</param>
/// <param name="userWidth">The device width, in user-specific units.</param>
/// <param name="userHeight">The device heigh, in user-specific units.</param>
/// <param name="stretchMode">
/// A value indicating how to stretch user-specific units to fit the device units.
/// </param>
/// <returns>The created transformation matrix.</returns>
private Matrix CreateUserToDeviceTransformationMatrix(int deviceWidth, int deviceHeight,
double userWidth, double userHeight, UserToDeviceStretchMode stretchMode)
{
var extents = _currentScopeGraphicsRangeExtents;
var deviceCenter = new PointD(deviceWidth / 2 + extents.MinX, deviceHeight / 2 + extents.MinY);
var aspectRatioCalculator = new AspectRatioCalculator(deviceWidth, deviceHeight, userWidth, userHeight);
var aspectRatioFactor = aspectRatioCalculator.UserToDeviceAspectRatioFactor;
switch (stretchMode)
{
case UserToDeviceStretchMode.UniformToAny:
stretchMode = aspectRatioFactor > 1 ? UserToDeviceStretchMode.UniformToHeight : UserToDeviceStretchMode.UniformToWidth;
break;
case UserToDeviceStretchMode.UniformToFill:
stretchMode = aspectRatioFactor < 1 ? UserToDeviceStretchMode.UniformToHeight : UserToDeviceStretchMode.UniformToWidth;
break;
}
switch (stretchMode)
{
case UserToDeviceStretchMode.UniformToHeight:
userWidth = userHeight;
deviceWidth = (int)(deviceWidth / aspectRatioCalculator.DeviceAspectRatio);
break;
case UserToDeviceStretchMode.UniformToWidth:
userHeight = userWidth;
deviceHeight = (int)(deviceHeight * aspectRatioCalculator.DeviceAspectRatio);
break;
}
return(new Matrix(deviceWidth / userWidth, 0, 0, -deviceHeight / userHeight, deviceCenter.X, deviceCenter.Y));
}
/// <summary>
/// Creates a rectangle range the scope contents are rendered to, according to the specified values.
/// </summary>
/// <returns>The user range.</returns>
/// <param name="extents">The extents of the device area to render to.</param>
/// <param name="xUserMinSpan">The minimum horizontal (X) span requeste, in user-specific units.</param>
/// <param name="yUserMinSpan">The minimum vertical (Y) span requeste, in user-specific units.</param>
/// <param name="originOffset">The offset of the origin to the range center, in user-specific units.</param>
/// <returns>The created rectangle range or <c>null</c> if no range could be created.</returns>
private RectangleRange CreateScopeGraphicsRange(DeviceAreaExtents extents,
double xUserMinSpan, double yUserMinSpan, Distance userOriginOffset)
{
var rangeWidth = extents.Width;
var rangeHeight = extents.Height;
// As this could result in division by zero or infinite values,
// we don't create a range in this case.
if (rangeWidth <= 0 || rangeHeight <= 0)
{
return(null);
}
double aspectRatioFactor;
UserToDeviceStretchMode userToDeviceStretchMode;
if (_stretchMode == ScopeStretchMode.Expand)
{
aspectRatioFactor = new AspectRatioCalculator(rangeWidth, rangeHeight, xUserMinSpan, yUserMinSpan)
.UserToDeviceAspectRatioFactor;
userToDeviceStretchMode = UserToDeviceStretchMode.UniformToAny;
}
else
{
aspectRatioFactor = 1;
userToDeviceStretchMode = UserToDeviceStretchMode.Fill;
}
// Expand the width or height range to utilize any extra space available.
var xUserSpan = xUserMinSpan;
var yUserSpan = yUserMinSpan;
if (aspectRatioFactor > 1)
{
xUserSpan *= aspectRatioFactor;
}
else
{
yUserSpan /= aspectRatioFactor;
}
var userToDeviceMatrix = CreateUserToDeviceTransformationMatrix(rangeWidth, rangeHeight, xUserSpan, yUserSpan, userToDeviceStretchMode);
// Note: "if (matrix != null)" fails. Bug in the equality operator of Matrix?
// Consider the origin offset (in user-specific units).
userToDeviceMatrix.Translate(+userOriginOffset.Dx, +userOriginOffset.Dy);
return(new RectangleRange(rangeWidth, rangeHeight, xUserSpan, yUserSpan, userOriginOffset, userToDeviceMatrix));
}