/// <summary>
/// Implementation of method required by the <see cref="T:XFGloss.IGradientRenderer"/> interface. Updates
/// the gradient fill steps being used by any existing implementation of the property specified by the
/// propertyName parameter.
/// </summary>
/// <param name="propertyName">The name of the XFGloss attached BindableProperty that changed</param>
/// <param name="steps">The new collection of <see cref="T:XFGloss.GradientStep"/> instances that specify the
/// colors and positions of each step of the gradient fill</param>
public void UpdateSteps(string propertyName, GradientStepCollection steps)
{
// No need to check property name yet, BackgroundGradient is the only one being handled here.
var nativeCell = GetNativeCell();
if (nativeCell != null)
{
GetBackgroundGradientDrawable(nativeCell)?.UpdateSteps(steps);
}
}
/// <summary>
/// Helper function that converts a list of Xamarin.Forms.Color instances to iOS CGColor instances
/// </summary>
/// <returns>An array of CGColor instances</returns>
/// <param name="steps">The colection of <see cref="T:XFGloss.GradientStep"/> instances to be converted</param>
static CGColor[] ToCGColors(GradientStepCollection steps)
{
List <CGColor> result = new List <CGColor>();
foreach (GradientStep step in steps)
{
result.Add(step.StepColor.ToCGColor());
}
return(result.ToArray());
}
/// <summary>
/// Provides public access to update the <see cref="T:XFGloss.GradientStepCollection"/> of
/// <see cref="T:XFGloss.GradientStep"/> instances for an existing gradient fill.
/// </summary>
/// <param name="steps">The new gradient steps to be applied to the existing gradient fill</param>
public void UpdateSteps(GradientStepCollection steps)
{
if (_xfgGradient == null)
{
return;
}
var sf = GetShaderFactory();
sf?.Dispose();
_xfgGradient.Steps = steps;
sf = new XFGlossShaderFactory(_xfgGradient, _shaderMatrix);
SetShaderFactory(sf);
Paint.Shader?.Dispose();
Paint.SetShader(sf.Resize(Bounds.Width(), Bounds.Height()));
}
/// <summary>
/// Updates an existing gradient layer's colors and position percentage values, if found
/// </summary>
/// <param name="steps">The <see cref="T:XFGloss.GradientStepCollection"/> of
/// <see cref="T:XFGloss.GradientStep"/> instances</param>
public void UpdateSteps(GradientStepCollection steps)
{
var gradient = GradientSource ?? new Gradient();
if (gradient != null && !gradient.Steps.Equals(steps))
{
gradient.Steps = new GradientStepCollection(steps);
Colors = ToCGColors(steps);
Locations = ToNSNumbers(steps);
if (GradientSource == null)
{
GradientSource = gradient;
}
else
{
GradientSource.Steps = gradient.Steps;
}
}
}
/// <summary>
/// Helper function that converts a list of step percentages to NSNumbers
/// </summary>
/// <returns>An array of NSNumber instances</returns>
/// <param name="steps">The colection of <see cref="T:XFGloss.GradientStep"/> instances to be converted</param>
static public NSNumber[] ToNSNumbers(GradientStepCollection steps)
{
List <NSNumber> result = new List <NSNumber>();
float lastStep = float.MinValue;
foreach (GradientStep step in steps)
{
if (lastStep > step.StepPercentage)
{
throw new ArgumentOutOfRangeException(nameof(GradientStep.StepPercentage), "The current StepPercentage " +
"value must be greater than zero and the previous " +
" StepPercentage value.");
}
result.Add(new NSNumber(step.StepPercentage));
}
return(result.ToArray());
}
/// <summary>
/// Implementation of method required by the <see cref="T:XFGloss.IGradientRenderer"/> interface. Updates
/// the gradient fill steps being used by any existing implementation of the property specified by the
/// propertyName parameter.
/// </summary>
/// <param name="propertyName">The name of the XFGloss attached BindableProperty that changed</param>
/// <param name="steps">The new collection of <see cref="T:XFGloss.GradientStep"/> instances that specify the
/// colors and positions of each step of the gradient fill</param>
public void UpdateSteps(string propertyName, GradientStepCollection steps)
{
// No need to check property name yet, BackgroundGradient is the only one being handled here.
XFGlossGradientLayer.GetGradientLayer(NativeView)?.UpdateSteps(steps);
}
/// <summary>
/// Implementation of method required by the <see cref="T:XFGloss.IGradientRenderer"/> interface. Updates
/// the gradient fill steps being used by any existing implementation of the property specified by the
/// propertyName parameter.
/// </summary>
/// <param name="propertyName">The name of the XFGloss attached BindableProperty that changed</param>
/// <param name="steps">The new collection of <see cref="T:XFGloss.GradientStep"/> instances that specify the
/// colors and positions of each step of the gradient fill</param>
public void UpdateSteps(string propertyName, GradientStepCollection steps)
{
// No need to check property name yet, BackgroundGradient is the only one being handled here.
GetBackgroundGradientDrawable()?.UpdateSteps(steps);
Invalidate();
}
/// <summary>
/// Updates the associated <see cref="T:XFGloss.iOS.Views.XFGlossGradientLayer"/> instance's steps collection.
/// </summary>
/// <param name="steps">The steps collection to assign</param>
public void UpdateSteps(GradientStepCollection steps)
{
var layer = XFGlossGradientLayer.GetGradientLayer(this);
layer?.UpdateSteps(steps);
}