/// <summary>
/// Initializes a new instance of the <see cref="SDL2Surface2D"/> class.
/// </summary>
/// <param name="uv">The Ultraviolet context.</param>
/// <param name="nativesurf">The native SDL surface that this object represents.</param>
/// <param name="options">The surface's configuration options.</param>
public SDL2Surface2D(UltravioletContext uv, PlatformNativeSurface nativesurf, SurfaceOptions options)
: base(uv)
{
if (nativesurf == null)
{
throw new ArgumentNullException(nameof(nativesurf));
}
var isSrgb = (options & SurfaceOptions.SrgbColor) == SurfaceOptions.SrgbColor;
var isLinear = (options & SurfaceOptions.LinearColor) == SurfaceOptions.LinearColor;
if (isSrgb && isLinear)
{
throw new ArgumentException(UltravioletStrings.SurfaceCannotHaveMultipleEncodings);
}
this.nativesurf = (SDL2PlatformNativeSurface)nativesurf;
this.SrgbEncoded = isLinear ? false : (isSrgb ? true : uv.Properties.SrgbDefaultForSurface2D);
}
/// <summary>
/// Identifies the positions of the glyphs on the specified surface.
/// </summary>
/// <param name="surface">The surface on which to identify glyphs.</param>
/// <param name="source">The region on the surface in which to look for glyphs, or null to examine the entire surface.</param>
/// <returns>A collection of rectangles describing the positions of the glyphs on the specified surface.</returns>
public static IEnumerable <Rectangle> IdentifyGlyphs(PlatformNativeSurface surface, Rectangle?source = null)
{
if (source.HasValue && (source.Value.Width > surface.Width | source.Value.Height > surface.Height))
{
throw new ArgumentOutOfRangeException("source");
}
var regionValue = source ?? new Rectangle(0, 0, surface.Width, surface.Height);
var data = new Color[regionValue.Width * regionValue.Height];
surface.GetData(data, regionValue);
// Find the glyphs on the texture.
var positions = new List <Rectangle>();
var nextLine = 0;
var nextGlyph = 0;
for (int y = 0; y < regionValue.Height; y = nextLine)
{
nextLine = y + 1;
for (int x = 0; x < regionValue.Width; x = nextGlyph)
{
nextGlyph = x + 1;
// Skip buffer pixels.
var pixel = data[y * regionValue.Width + x];
if (pixel.Equals(Color.Magenta))
{
continue;
}
// Find the width of the glyph.
var x2 = x + 1;
while (x2 < regionValue.Width)
{
if (data[y * regionValue.Width + x2++].Equals(Color.Magenta))
{
break;
}
}
var glyphWidth = (x2 - x) - 1;
// Find the height of the glyph.
var y2 = y + 1;
while (y2 < regionValue.Height)
{
if (data[y2++ *regionValue.Width + x].Equals(Color.Magenta))
{
break;
}
}
var glyphHeight = (y2 - y) - 1;
// Calculate the position of the next glyph and the next line of glyphs.
nextGlyph = x + glyphWidth + 1;
if (y + glyphHeight > nextLine)
{
nextLine = y + glyphHeight + 1;
}
// Store the glyph's position.
positions.Add(new Rectangle(regionValue.X + x, regionValue.Y + y, glyphWidth, glyphHeight));
}
}
return(positions);
}
