/// <summary>
/// Returns true if this color is less than or equal to reference color on all channels.
/// </summary>
/// <param name="reference">The reference color to evaluate against.</param>
/// <returns>True if this color is less than or equal to reference on all channels.</returns>
internal bool MeetsTolerance(ColorDifference reference)
{
return((this.A <= reference.A) &&
(this.R <= reference.R) &&
(this.G <= reference.G) &&
(this.B <= reference.B));
}
/// <summary>
/// Performs Bitwise AND of Color bits.
/// </summary>
/// <param name="color1">The first color.</param>
/// <param name="color2">The second color.</param>
/// <returns></returns>
internal static Color And(this Color color1, Color color2)
{
ColorDifference andValue = new ColorDifference();
andValue.A = (byte)(color1.A & color2.A);
andValue.R = (byte)(color1.R & color2.R);
andValue.G = (byte)(color1.G & color2.G);
andValue.B = (byte)(color1.B & color2.B);
return(Color.FromArgb(andValue.A, andValue.R, andValue.G, andValue.B));
}
/// <summary>
/// Performs Bitwise OR of Color bits.
/// </summary>
/// <param name="color1">The first color.</param>
/// <param name="color2">The second color.</param>
/// <returns></returns>
internal static Color Or(this Color color1, Color color2)
{
ColorDifference orValue = new ColorDifference();
orValue.A = (byte)(color1.A | color2.A);
orValue.R = (byte)(color1.R | color2.R);
orValue.G = (byte)(color1.G | color2.G);
orValue.B = (byte)(color1.B | color2.B);
return(Color.FromArgb(orValue.A, orValue.R, orValue.G, orValue.B));
}
/// <summary>
/// Color differencing helper for snapshot comparisons.
/// </summary>
/// <param name="color1">The first color</param>
/// <param name="color2">The second color</param>
/// <param name="subtractAlpha">If set to false, the Alpha channel is overridden to full opacity, rather than the difference.
/// This is important for visualization, especially if both colors are fully opaque, as the difference produces a fully transparent difference.</param>
/// <returns></returns>
internal static Color Subtract(this Color color1, Color color2, bool subtractAlpha)
{
ColorDifference diff = Compare(color1, color2);
if (!subtractAlpha)
{
diff.A = 255;
}
return(Color.FromArgb(diff.A, diff.R, diff.G, diff.B));
}
/// <summary>
/// Compares colors by producing an absolute valued Color Difference object
/// </summary>
/// <param name="color1">The first color</param>
/// <param name="color2">The second colar</param>
/// <returns>The Color Difference of the two colors</returns>
internal static ColorDifference Compare(this Color color1, Color color2)
{
ColorDifference diff = new ColorDifference();
diff.A = (byte)Math.Abs(color1.A - color2.A);
diff.R = (byte)Math.Abs(color1.R - color2.R);
diff.G = (byte)Math.Abs(color1.G - color2.G);
diff.B = (byte)Math.Abs(color1.B - color2.B);
return(diff);
}
/// <summary>
/// Ensures that the image colors are all within tolerance range of the expected Color.
/// </summary>
/// <param name="image">The actual image being verified.</param>
/// <returns>A VerificationResult enumeration value based on the image, the expected color, and the tolerance.</returns>
public override VerificationResult Verify(Snapshot image)
{
for (int row = 0; row < image.Height; row++)
{
for (int column = 0; column < image.Width; column++)
{
ColorDifference diff = image[row, column].Compare(ExpectedColor);
if (!diff.MeetsTolerance(Tolerance))
{
//Exit early as we have a counter-example to prove failure.
return(VerificationResult.Fail);
}
}
}
return(VerificationResult.Pass);
}
/// <summary>
/// Initializes a new instance of the SnapshotColorVerifier class, using the specified tolerance value.
/// </summary>
/// <param name="expectedColor">The expected color to test against.</param>
/// <param name="tolerance">A ColorDifference instance specifying the desired tolerance.</param>
public SnapshotColorVerifier(Color expectedColor, ColorDifference tolerance)
{
this.Tolerance = tolerance;
this.ExpectedColor = expectedColor;
}
/// <summary>
/// Initializes a new instance of a SnapshotColorVerifier class, using black pixels with zero tolerance.
/// </summary>
public SnapshotColorVerifier()
{
Tolerance = new ColorDifference();
ExpectedColor = Color.Black;
}