Question

我正在开发一款Kivy应用，让用户可以在模板上定位图像和文字标签。完成后，将裁剪生成的图像以适合模板。

我需要清除图像中的所有空白区域，因为我将打印图像并且不想浪费墨水。然而，Kivy用黑色填充所有空白区域。有没有办法让Kivy的export_to_png（）函数使用透明背景而不是黑色背景？

Answer 1

我可能错了，但看起来透明色是硬编码的。

查看source code似乎ClearColor被硬编码为黑色。

def export_to_png(self, filename, *args):
        '''Saves an image of the widget and its children in png format at the
        specified filename. Works by removing the widget canvas from its
        parent, rendering to an :class:`~kivy.graphics.fbo.Fbo`, and calling
        :meth:`~kivy.graphics.texture.Texture.save`.

        .. note::

            The image includes only this widget and its children. If you want
            to include widgets elsewhere in the tree, you must call
            :meth:`~Widget.export_to_png` from their common parent, or use
            :meth:`~kivy.core.window.WindowBase.screenshot` to capture the whole
            window.

        .. note::

            The image will be saved in png format, you should include the
            extension in your filename.

        .. versionadded:: 1.9.0
        '''

        if self.parent is not None:
            canvas_parent_index = self.parent.canvas.indexof(self.canvas)
            self.parent.canvas.remove(self.canvas)

        fbo = Fbo(size=self.size, with_stencilbuffer=True)

        with fbo:
            ClearColor(0, 0, 0, 1)
            ClearBuffers()
            Scale(1, -1, 1)
            Translate(-self.x, -self.y - self.height, 0)

我想您可以尝试更新Widget模块代码以接受参数来设置ClearColor。

Kivy以清晰的背景拍摄截图

1 个答案: