public static void Xfermode(SKCanvas canvas, int width, int height)
{
var modes = Enum.GetValues(typeof(SKXferMode)).Cast <SKXferMode> ().ToArray();
var cols = width < height ? 3 : 5;
var rows = (modes.Length - 1) / cols + 1;
var w = (float)width / cols;
var h = (float)height / rows;
var rect = SKRect.Create(w, h);
var srcPoints = new[] {
new SKPoint(0.0f, 0.0f),
new SKPoint(w, 0.0f)
};
var srcColors = new [] {
SKColors.Magenta.WithAlpha(0),
SKColors.Magenta
};
var dstPoints = new [] {
new SKPoint(0.0f, 0.0f),
new SKPoint(0.0f, h)
};
var dstColors = new [] {
SKColors.Cyan.WithAlpha(0),
SKColors.Cyan
};
using (var text = new SKPaint())
using (var stroke = new SKPaint())
using (var src = new SKPaint())
using (var dst = new SKPaint())
using (var srcShader = SKShader.CreateLinearGradient(srcPoints [0], srcPoints [1], srcColors, null, SKShaderTileMode.Clamp))
using (var dstShader = SKShader.CreateLinearGradient(dstPoints [0], dstPoints [1], dstColors, null, SKShaderTileMode.Clamp)) {
text.TextSize = 12.0f;
text.IsAntialias = true;
text.TextAlign = SKTextAlign.Center;
stroke.IsStroke = true;
src.Shader = srcShader;
dst.Shader = dstShader;
canvas.Clear(SKColors.White);
for (var i = 0; i < modes.Length; ++i)
{
using (new SKAutoCanvasRestore(canvas, true)) {
canvas.Translate(w * (i / rows), h * (i % rows));
canvas.ClipRect(rect);
canvas.DrawColor(SKColors.LightGray);
canvas.SaveLayer(null);
canvas.Clear(SKColors.Transparent);
canvas.DrawPaint(dst);
src.XferMode = modes [i];
canvas.DrawPaint(src);
canvas.DrawRect(rect, stroke);
var desc = modes [i].ToString();
canvas.DrawText(desc, w / 2f, h / 2f, text);
}
}
}
}
private void ReadElement(XElement e, SKCanvas canvas, SKPaint stroke, SKPaint fill)
{
// transform matrix
var transform = ReadTransform(e.Attribute("transform")?.Value ?? string.Empty);
canvas.Save();
canvas.Concat(ref transform);
// SVG element
var elementName = e.Name.LocalName;
var isGroup = elementName == "g";
// read style
var style = ReadPaints(e, ref stroke, ref fill, isGroup);
// parse elements
switch (elementName)
{
case "text":
if (stroke != null || fill != null)
{
ReadText(e, canvas, stroke?.Clone(), fill?.Clone());
}
break;
case "rect":
if (stroke != null || fill != null)
{
var x = ReadNumber(e.Attribute("x"));
var y = ReadNumber(e.Attribute("y"));
var width = ReadNumber(e.Attribute("width"));
var height = ReadNumber(e.Attribute("height"));
var rx = ReadNumber(e.Attribute("rx"));
var ry = ReadNumber(e.Attribute("ry"));
var rect = SKRect.Create(x, y, width, height);
if (rx > 0 || ry > 0)
{
if (fill != null)
{
canvas.DrawRoundRect(rect, rx, ry, fill);
}
if (stroke != null)
{
canvas.DrawRoundRect(rect, rx, ry, stroke);
}
}
else
{
if (fill != null)
{
canvas.DrawRect(rect, fill);
}
if (stroke != null)
{
canvas.DrawRect(rect, stroke);
}
}
}
break;
case "ellipse":
if (stroke != null || fill != null)
{
var cx = ReadNumber(e.Attribute("cx"));
var cy = ReadNumber(e.Attribute("cy"));
var rx = ReadNumber(e.Attribute("rx"));
var ry = ReadNumber(e.Attribute("ry"));
if (fill != null)
{
canvas.DrawOval(cx, cy, rx, ry, fill);
}
if (stroke != null)
{
canvas.DrawOval(cx, cy, rx, ry, stroke);
}
}
break;
case "circle":
if (stroke != null || fill != null)
{
var cx = ReadNumber(e.Attribute("cx"));
var cy = ReadNumber(e.Attribute("cy"));
var rr = ReadNumber(e.Attribute("r"));
if (fill != null)
{
canvas.DrawCircle(cx, cy, rr, fill);
}
if (stroke != null)
{
canvas.DrawCircle(cx, cy, rr, stroke);
}
}
break;
case "path":
if (stroke != null || fill != null)
{
var d = e.Attribute("d")?.Value;
if (!string.IsNullOrWhiteSpace(d))
{
var path = SKPath.ParseSvgPathData(d);
if (fill != null)
{
canvas.DrawPath(path, fill);
}
if (stroke != null)
{
canvas.DrawPath(path, stroke);
}
}
}
break;
case "polygon":
case "polyline":
if (stroke != null || fill != null)
{
var close = elementName == "polygon";
var p = e.Attribute("points")?.Value;
if (!string.IsNullOrWhiteSpace(p))
{
var path = ReadPolyPath(p, close);
if (fill != null)
{
canvas.DrawPath(path, fill);
}
if (stroke != null)
{
canvas.DrawPath(path, stroke);
}
}
}
break;
case "g":
if (e.HasElements)
{
// get current group opacity
float groupOpacity = ReadOpacity(style);
if (groupOpacity != 1.0f)
{
var opacity = (byte)(255 * groupOpacity);
var opacityPaint = new SKPaint {
Color = SKColors.Black.WithAlpha(opacity)
};
// apply the opacity
canvas.SaveLayer(opacityPaint);
}
foreach (var gElement in e.Elements())
{
ReadElement(gElement, canvas, stroke?.Clone(), fill?.Clone());
}
// restore state
if (groupOpacity != 1.0f)
{
canvas.Restore();
}
}
break;
case "use":
if (e.HasAttributes)
{
var href = ReadHref(e);
if (href != null)
{
// TODO: copy/process other attributes
var x = ReadNumber(e.Attribute("x"));
var y = ReadNumber(e.Attribute("y"));
var useTransform = SKMatrix.MakeTranslation(x, y);
canvas.Save();
canvas.Concat(ref useTransform);
ReadElement(href, canvas, stroke?.Clone(), fill?.Clone());
canvas.Restore();
}
}
break;
case "line":
if (stroke != null)
{
var x1 = ReadNumber(e.Attribute("x1"));
var x2 = ReadNumber(e.Attribute("x2"));
var y1 = ReadNumber(e.Attribute("y1"));
var y2 = ReadNumber(e.Attribute("y2"));
canvas.DrawLine(x1, y1, x2, y2, stroke);
}
break;
case "switch":
if (e.HasElements)
{
foreach (var ee in e.Elements())
{
var requiredFeatures = ee.Attribute("requiredFeatures");
var requiredExtensions = ee.Attribute("requiredExtensions");
var systemLanguage = ee.Attribute("systemLanguage");
// TODO: evaluate requiredFeatures, requiredExtensions and systemLanguage
var isVisible =
requiredFeatures == null &&
requiredExtensions == null &&
systemLanguage == null;
if (isVisible)
{
ReadElement(ee, canvas, stroke?.Clone(), fill?.Clone());
}
}
}
break;
case "defs":
case "title":
case "desc":
case "description":
// already read earlier
break;
default:
LogOrThrow($"SVG element '{elementName}' is not supported");
break;
}
// restore matrix
canvas.Restore();
}
public static void Xfermode (SKCanvas canvas, int width, int height)
{
var modes = Enum.GetValues (typeof(SKXferMode)).Cast<SKXferMode> ().ToArray ();
var cols = width < height ? 3 : 5;
var rows = (modes.Length - 1) / cols + 1;
var w = (float)width / cols;
var h = (float)height / rows;
var rect = SKRect.Create (w, h);
var srcPoints = new[] {
new SKPoint (0.0f, 0.0f),
new SKPoint (w, 0.0f)
};
var srcColors = new [] {
SKColors.Magenta.WithAlpha (0),
SKColors.Magenta
};
var dstPoints = new [] {
new SKPoint (0.0f, 0.0f),
new SKPoint (0.0f, h)
};
var dstColors = new [] {
SKColors.Cyan.WithAlpha (0),
SKColors.Cyan
};
using (var text = new SKPaint ())
using (var stroke = new SKPaint ())
using (var src = new SKPaint ())
using (var dst = new SKPaint ())
using (var srcShader = SKShader.CreateLinearGradient (srcPoints [0], srcPoints [1], srcColors, null, SKShaderTileMode.Clamp))
using (var dstShader = SKShader.CreateLinearGradient (dstPoints [0], dstPoints [1], dstColors, null, SKShaderTileMode.Clamp)) {
text.TextSize = 12.0f;
text.IsAntialias = true;
text.TextAlign = SKTextAlign.Center;
stroke.IsStroke = true;
src.Shader = srcShader;
dst.Shader = dstShader;
canvas.Clear (SKColors.White);
for (var i = 0; i < modes.Length; ++i) {
using (new SKAutoCanvasRestore (canvas, true)) {
canvas.Translate (w * (i / rows), h * (i % rows));
canvas.ClipRect (rect);
canvas.DrawColor (SKColors.LightGray);
canvas.SaveLayer (null);
canvas.Clear (SKColors.Transparent);
canvas.DrawPaint (dst);
src.XferMode = modes [i];
canvas.DrawPaint (src);
canvas.DrawRect (rect, stroke);
var desc = modes [i].ToString ();
canvas.DrawText (desc, w / 2f, h / 2f, text);
}
}
}
}
){kind=link}