/// <summary>
/// Calculates the matrix to transform the content by to fit into the specified viewport dimensions
/// </summary>
public static SvgMatrix CalculateViewboxFit(this ISvgFitToViewbox fitToViewbox, float viewportWidth, float viewportHeight)
{
CalculateViewboxFit(fitToViewbox, viewportWidth, viewportHeight, out var scaleX, out var scaleY, out var offsetX, out var offsetY);
var translateMatrix = SvgMatrix.CreateTranslate(offsetX, offsetY);
var scaleMatrix = SvgMatrix.CreateScale(scaleX, scaleY);
return(SvgMatrix.Multiply(translateMatrix, scaleMatrix));
}
private bool PushViewportMatrixIfValid(ISvgFitToViewbox fitToViewbox, float viewportWidth, float viewportHeight)
{
if (viewportWidth <= 0 || viewportHeight <= 0)
{
return(false);
}
var matrix = fitToViewbox.CalculateViewboxFit(viewportWidth, viewportHeight);
PushMatrix(matrix);
return(true);
}
private PageElement EstablishViewportThen <TArg>(ISvgFitToViewbox fitToViewbox, float viewportWidth, float viewportHeight, Func <TArg, PageElement> transform, TArg arg)
{
ClippingGroup result = null;
var matrix = CurrentMatrix;
if (PushViewportMatrixIfValid(fitToViewbox, viewportWidth, viewportHeight))
{
SvgMatrix.Multiply(matrix, 0, 0, out var xMin, out var yMin);
SvgMatrix.Multiply(matrix, viewportWidth, viewportHeight, out var xMax, out var yMax);
result = new ClippingGroup(xMin, yMin, xMax, yMax, transform(arg));
PopMatrix();
}
return(result);
}
/// <summary>
/// Calculates the scale and offset values to transform the content by to fit into the specified viewport dimensions
/// </summary>
public static void CalculateViewboxFit(this ISvgFitToViewbox fitToViewbox, float viewportWidth, float viewportHeight, out float scaleX, out float scaleY, out float offsetX, out float offsetY)
{
if (fitToViewbox == null)
{
throw new ArgumentNullException(nameof(fitToViewbox));
}
var viewBox = fitToViewbox.ViewBox ?? new SvgRect(0, 0, viewportWidth, viewportHeight);
var preserveAspectRatio = fitToViewbox.PreserveAspectRatio;
var meetOrSliceFlag = preserveAspectRatio?.MeetOrSlice ?? SvgPreserveAspectRatioMeetOrSlice.Meet;
var alignFlag = preserveAspectRatio?.Align ?? SvgPreserveAspectRatioAlign.XMidYMid;
scaleX = viewportWidth / viewBox.Width;
scaleY = viewportHeight / viewBox.Height;
float uniformScale;
switch (meetOrSliceFlag)
{
case SvgPreserveAspectRatioMeetOrSlice.Meet:
uniformScale = Math.Min(scaleX, scaleY);
break;
case SvgPreserveAspectRatioMeetOrSlice.Slice:
uniformScale = Math.Max(scaleX, scaleY);
break;
default:
throw new ArgumentOutOfRangeException();
}
if (alignFlag != SvgPreserveAspectRatioAlign.None)
{
scaleX = scaleY = uniformScale;
}
var xMin = -viewBox.X;
var yMin = -viewBox.Y;
var xMid = xMin + (viewportWidth - viewBox.Width * scaleX) * 0.5f;
var yMid = yMin + (viewportHeight - viewBox.Height * scaleY) * 0.5f;
var xMax = xMin + (viewportWidth - viewBox.Width * scaleX);
var yMax = yMin + (viewportHeight - viewBox.Height * scaleY);
switch (alignFlag)
{
case SvgPreserveAspectRatioAlign.None:
offsetX = offsetY = 0;
break;
case SvgPreserveAspectRatioAlign.XMinYMin:
offsetX = xMin;
offsetY = yMin;
break;
case SvgPreserveAspectRatioAlign.XMidYMin:
offsetX = xMid;
offsetY = yMin;
break;
case SvgPreserveAspectRatioAlign.XMaxYMin:
offsetX = xMax;
offsetY = yMin;
break;
case SvgPreserveAspectRatioAlign.XMinYMid:
offsetX = xMin;
offsetY = yMid;
break;
case SvgPreserveAspectRatioAlign.XMidYMid:
offsetX = xMid;
offsetY = yMid;
break;
case SvgPreserveAspectRatioAlign.XMaxYMid:
offsetX = xMax;
offsetY = yMid;
break;
case SvgPreserveAspectRatioAlign.XMinYMax:
offsetX = xMin;
offsetY = yMax;
break;
case SvgPreserveAspectRatioAlign.XMidYMax:
offsetX = xMid;
offsetY = yMax;
break;
case SvgPreserveAspectRatioAlign.XMaxYMax:
offsetX = xMax;
offsetY = yMax;
break;
default:
throw new ArgumentOutOfRangeException();
}
}
