SkiaSharp drawing image with GPU acceleration
I want to draw something with GPU acceleration in xamarin.forms. (and save the image later). When I call the following method the first time, I get an image and can show it in SKGLView. But when I call the method again, there is nothing (no error, too)
Can somebody give me a hint?
private SKImage CreateSKImage()
{
SKImage sKImage;
var glInterface = GRGlInterface.CreateNativeAngleInterface();
var grContext = GRContext.Create(GRBackend.OpenGL, glInterface);
var surface = SKSurface.Create(grContext, true, new SKImageInfo(500, 500));
var canvas = surface.Canvas;
var paintStroke = new SKPaint
{
IsAntialias = true,
Style = SKPaintStyle.Stroke,
Color = SKColors.Purple,
StrokeWidth = 1
};
canvas.DrawLine(new SKPoint(0, 0), new SKPoint(500, 500), paintStroke);
surface.Canvas.Flush();
sKImage = surface.Snapshot().ToRasterImage();
return sKImage;
}
edit: when I call the method from SKGLView onPaint, then I get something. But when I call the method from anywhere else the glInterface is null ...hmmmm
How to create the OpenGL Interface the right way???
xamarin.forms gpu skiasharp
asked Nov 18 '18 at 12:25
alpha kevin
62
add a comment |
I want to draw something with GPU acceleration in xamarin.forms. (and save the image later). When I call the following method the first time, I get an image and can show it in SKGLView. But when I call the method again, there is nothing (no error, too)
Can somebody give me a hint?
private SKImage CreateSKImage()
{
SKImage sKImage;
var glInterface = GRGlInterface.CreateNativeAngleInterface();
var grContext = GRContext.Create(GRBackend.OpenGL, glInterface);
var surface = SKSurface.Create(grContext, true, new SKImageInfo(500, 500));
var canvas = surface.Canvas;
var paintStroke = new SKPaint
{
IsAntialias = true,
Style = SKPaintStyle.Stroke,
Color = SKColors.Purple,
StrokeWidth = 1
};
canvas.DrawLine(new SKPoint(0, 0), new SKPoint(500, 500), paintStroke);
surface.Canvas.Flush();
sKImage = surface.Snapshot().ToRasterImage();
return sKImage;
}
edit: when I call the method from SKGLView onPaint, then I get something. But when I call the method from anywhere else the glInterface is null ...hmmmm
How to create the OpenGL Interface the right way???
xamarin.forms gpu skiasharp
asked Nov 18 '18 at 12:25
alpha kevin
62
Make sure you're calling this on the main thread if you intend to use the opengl context that SKGLView is using. OpenGL restricts each context to a particular thread and only one context can be active at time, SKGLView uses GLControl as a baseclass which handles context creation on the UI Thread. Here's a resource for reading more about opengl contexts: khronos.org/opengl/wiki/OpenGL_Context
– jake.lange
Nov 21 '18 at 2:45
add a comment |
I want to draw something with GPU acceleration in xamarin.forms. (and save the image later). When I call the following method the first time, I get an image and can show it in SKGLView. But when I call the method again, there is nothing (no error, too)
Can somebody give me a hint?
private SKImage CreateSKImage()
{
SKImage sKImage;
var glInterface = GRGlInterface.CreateNativeAngleInterface();
var grContext = GRContext.Create(GRBackend.OpenGL, glInterface);
var surface = SKSurface.Create(grContext, true, new SKImageInfo(500, 500));
var canvas = surface.Canvas;
var paintStroke = new SKPaint
{
IsAntialias = true,
Style = SKPaintStyle.Stroke,
Color = SKColors.Purple,
StrokeWidth = 1
};
canvas.DrawLine(new SKPoint(0, 0), new SKPoint(500, 500), paintStroke);
surface.Canvas.Flush();
sKImage = surface.Snapshot().ToRasterImage();
return sKImage;
}
edit: when I call the method from SKGLView onPaint, then I get something. But when I call the method from anywhere else the glInterface is null ...hmmmm
How to create the OpenGL Interface the right way???
xamarin.forms gpu skiasharp
asked Nov 18 '18 at 12:25
alpha kevin
62
I want to draw something with GPU acceleration in xamarin.forms. (and save the image later). When I call the following method the first time, I get an image and can show it in SKGLView. But when I call the method again, there is nothing (no error, too)
Can somebody give me a hint?
private SKImage CreateSKImage()
{
SKImage sKImage;
var glInterface = GRGlInterface.CreateNativeAngleInterface();
var grContext = GRContext.Create(GRBackend.OpenGL, glInterface);
var surface = SKSurface.Create(grContext, true, new SKImageInfo(500, 500));
var canvas = surface.Canvas;
var paintStroke = new SKPaint
{
IsAntialias = true,
Style = SKPaintStyle.Stroke,
Color = SKColors.Purple,
StrokeWidth = 1
};
canvas.DrawLine(new SKPoint(0, 0), new SKPoint(500, 500), paintStroke);
surface.Canvas.Flush();
sKImage = surface.Snapshot().ToRasterImage();
return sKImage;
}
edit: when I call the method from SKGLView onPaint, then I get something. But when I call the method from anywhere else the glInterface is null ...hmmmm
How to create the OpenGL Interface the right way???
xamarin.forms gpu skiasharp
xamarin.forms gpu skiasharp
asked Nov 18 '18 at 12:25
alpha kevin
62
asked Nov 18 '18 at 12:25
alpha kevin
62
edited Nov 21 '18 at 0:15
asked Nov 18 '18 at 12:25
alpha kevin
62
asked Nov 18 '18 at 12:25
alpha kevin
62
asked Nov 18 '18 at 12:25
alpha kevin
62
62
Make sure you're calling this on the main thread if you intend to use the opengl context that SKGLView is using. OpenGL restricts each context to a particular thread and only one context can be active at time, SKGLView uses GLControl as a baseclass which handles context creation on the UI Thread. Here's a resource for reading more about opengl contexts: khronos.org/opengl/wiki/OpenGL_Context
– jake.lange
Nov 21 '18 at 2:45
add a comment |
Make sure you're calling this on the main thread if you intend to use the opengl context that SKGLView is using. OpenGL restricts each context to a particular thread and only one context can be active at time, SKGLView uses GLControl as a baseclass which handles context creation on the UI Thread. Here's a resource for reading more about opengl contexts: khronos.org/opengl/wiki/OpenGL_Context
– jake.lange
Nov 21 '18 at 2:45
Make sure you're calling this on the main thread if you intend to use the opengl context that SKGLView is using. OpenGL restricts each context to a particular thread and only one context can be active at time, SKGLView uses GLControl as a baseclass which handles context creation on the UI Thread. Here's a resource for reading more about opengl contexts: khronos.org/opengl/wiki/OpenGL_Context
– jake.lange
Nov 21 '18 at 2:45
Make sure you're calling this on the main thread if you intend to use the opengl context that SKGLView is using. OpenGL restricts each context to a particular thread and only one context can be active at time, SKGLView uses GLControl as a baseclass which handles context creation on the UI Thread. Here's a resource for reading more about opengl contexts: khronos.org/opengl/wiki/OpenGL_Context
– jake.lange
Nov 21 '18 at 2:45
add a comment |
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Make sure you're calling this on the main thread if you intend to use the opengl context that SKGLView is using. OpenGL restricts each context to a particular thread and only one context can be active at time, SKGLView uses GLControl as a baseclass which handles context creation on the UI Thread. Here's a resource for reading more about opengl contexts: khronos.org/opengl/wiki/OpenGL_Context
– jake.lange
Nov 21 '18 at 2:45