如何在pysdl2中嵌入skia-python曲面

Question

我正试图将skia-python的曲面嵌入到窗口中，而不是输出到图像文件中。我使用pysdl2使用文档中的以下代码创建窗口：

import sys
import sdl2.ext
RESOURCES = sdl2.ext.Resources(__file__, "resources")
sdl2.ext.init()
window = sdl2.ext.Window("Hello World!", size=(640, 480))
window.show()
factory = sdl2.ext.SpriteFactory(sdl2.ext.SOFTWARE)
sprite = factory.from_image(RESOURCES.get_path("hello.bmp"))
spriterenderer = factory.create_sprite_render_system(window)
spriterenderer.render(sprite)
processor = sdl2.ext.TestEventProcessor()
processor.run(window)
sdl2.ext.quit()

这个代码从skia的文档中创建表面：

import skia
surface = skia.Surface(128, 128)
with surface as canvas:
rect = skia.Rect(32, 32, 96, 96)
paint = skia.Paint(
Color=skia.ColorBLUE,
Style=skia.Paint.kFill_Style)
canvas.drawRect(rect, paint)
image = surface.makeImageSnapshot()
image.save('output.png', skia.kPNG)

现在我想实现的是从skia部分获取image(或surface，以适用为准(对象，并将其插入pysdl2，这样我就可以使用skia绘制，但可以使用pysdl2处理窗口的事件循环，我现在想避免ctypes，因为我不太熟悉它。

Answer 1

我放弃了在没有ctypes的情况下创建它，因为我们只需要ctypes.byref，现在我正在导入sdl2而不是sdl2.ext，后者更像Python，但也限制了此处所需的一些功能。

现在为了回答这个问题，我在这里遵循了这个指南(如果你不是在构建浏览器，它可能会对你来说有点偏离主题(

所以我也从上面的指南中实现了一个足够通用的版本，你可以绘制到Window.skia_surface，然后调用Window.update将skia表面复制到窗口屏幕上：

import skia
import sdl2 as sdl
from ctypes import byref

def sdl_event_loop():
event = sdl.SDL_Event()
running = True
while running:
pending_events = sdl.SDL_PollEvent(byref(event))
while pending_events != 0:
# QUIT HANDLER
if event.type == sdl.SDL_QUIT:
running = False
sdl.SDL_Quit()
break
# UPDATE PENDING EVENTS
pending_events = sdl.SDL_PollEvent(byref(event))

class Window:
DEFAULT_FLAGS = sdl.SDL_WINDOW_SHOWN
BYTE_ORDER = {
# ---------- ->   RED        GREEN       BLUE        ALPHA
"BIG_ENDIAN": (0xff000000, 0x00ff0000, 0x0000ff00, 0x000000ff),
"LIL_ENDIAN": (0x000000ff, 0x0000ff00, 0x00ff0000, 0xff000000)
}
PIXEL_DEPTH = 32  # BITS PER PIXEL
PIXEL_PITCH_FACTOR = 4  # Multiplied by Width to get BYTES PER ROW
def __init__(self, title, width, height, x=None, y=None, flags=None):
self.title = bytes(title, "utf8")
self.width = width
self.height = height
# Center Window By default
self.x, self.y = x, y
if x is None:
self.x = sdl.SDL_WINDOWPOS_CENTERED
if y is None:
self.y = sdl.SDL_WINDOWPOS_CENTERED
# Override flags
self.flags = flags
if flags is None:
self.flags = self.DEFAULT_FLAGS
# SET RGBA MASKS BASED ON BYTE_ORDER
is_big_endian = sdl.SDL_BYTEORDER == sdl.SDL_BIG_ENDIAN
if is_big_endian:
self.RGBA_MASKS = self.BYTE_ORDER["BIG_ENDIAN"]
else:
self.RGBA_MASKS = self.BYTE_ORDER["LIL_ENDIAN"]
# CALCULATE PIXEL PITCH
self.PIXEL_PITCH = self.PIXEL_PITCH_FACTOR * self.width
# SKIA INIT
self.skia_surface = self.__create_skia_surface()
# SDL INIT
sdl.SDL_Init(sdl.SDL_INIT_EVENTS)  # INITIALIZE SDL EVENTS
self.sdl_window = self.__create_SDL_Window()
sdl_event_loop()
def __create_SDL_Window(self):
window = sdl.SDL_CreateWindow(
self.title,
self.x, self.y,
self.width, self.height,
self.flags
)
return window
def __create_skia_surface(self):
surface_blueprint = skia.ImageInfo.Make(
self.width, self.height,
ct=skia.kRGBA_8888_ColorType,
at=skia.kUnpremul_AlphaType
)
surface = skia.Surface.MakeRaster(surface_blueprint)
return surface
def __pixels_from_skia_surface(self):
image = self.skia_surface.makeImageSnapshot()
pixels = image.tobytes()
return pixels
def __transform_skia_surface_to_SDL_surface(self):
pixels = self.__pixels_from_skia_surface()
sdl_surface = sdl.SDL_CreateRGBSurfaceFrom(
pixels,
self.width, self.height,
self.PIXEL_DEPTH, self.PIXEL_PITCH,
*self.RGBA_MASKS
)
return sdl_surface
def update(self):
rect = sdl.SDL_Rect(0, 0, self.width, self.height)
window_surface = sdl.SDL_GetWindowSurface(self.sdl_window)  # the SDL surface associated with the window
transformed_skia_surface = self.__transform_skia_surface_to_SDL_surface()

# Transfer skia surface to SDL window's surface
sdl.SDL_BlitSurface(
transformed_skia_surface, rect,
window_surface, rect
)
# Update window with new copied data
sdl.SDL_UpdateWindowSurface(self.sdl_window)

if __name__ == "__main__":
window = Window("Browser Test", 500, 500, flags=sdl.SDL_WINDOW_SHOWN | sdl.SDL_WINDOW_RESIZABLE)

说明：上面的代码主要做四件事：创建一个您将在其上绘制的skia曲面，创建一个SDL窗口，将skia曲面转换为SDL曲面，最后将新创建的曲面中的数据复制到与该窗口关联的SDL曲面并更新它。关于更多的解释，我建议您查看上面的指南，并查看skia-python文档和SDL2的API参考资料。