Question

我正在开发一个Python + Gtk + Cairo应用程序。我的应用程序需要做一些非常复杂（和昂贵）的绘图。

出于性能原因，我首先在ImageSurface上绘制（在屏幕外），然后我会在DrawingArea对象上绘制ImageSurface内容。

NB： 我需要缩放/翻译我的图纸以使其可见; 否则，大型图纸会掉出窗外。

不幸的是，出了点问题：正如您所看到的，我无法绘制ImageSurface的全部内容。通过使用“规范”Context.set_source_surface（imageSurface，xCoord，yCoord） Context.paint（）

我的输出错误this：

This是我想要实现的结果：

如何强制绘制整个图像界面？

以下示例代码：

import gtk
import cairo

def main():
    w = gtk.Window()
    w.add(RubberTest())
    w.show_all()
    gtk.main()


class RubberTest(gtk.DrawingArea):
    def __init__(self, model=None):
        gtk.DrawingArea.__init__(self)
        self.set_size_request(800, 500)
        self.connect("expose-event", self._expose, self.create_basic_image())
        self.add_events(gtk.gdk.EXPOSURE_MASK
                      | gtk.gdk.BUTTON_PRESS_MASK
                      | gtk.gdk.BUTTON_RELEASE_MASK
                      | gtk.gdk.POINTER_MOTION_MASK)

    def create_basic_image(self):
        img = cairo.ImageSurface(cairo.FORMAT_ARGB32, 24, 24)
        cr = cairo.Context(img)

        # due to large coordinates, the drawing fall out of the window
        self.points = [(10000, 10000), (790000, 10000), (790000, 490000), (10000, 490000)]

        xMax, yMax, xMin, yMin = max([c[0] for c in self.points]), max([c[1] for c in self.points]), min([c[0] for c in self.points]), min([c[1] for c in self.points])
        maxRectWidth = xMax - xMin
        maxRectHeight = yMax - yMin

        w = 800
        h = 500
        width_ratio = float(w) / maxRectWidth
        height_ratio = float(h) / maxRectHeight

        # scale factor
        scaleFactor = min(height_ratio, width_ratio)

        cr.set_line_width(4)
        cr.set_source_rgb(1, 0, 0)

        cr.save()

        # scale + translate
        cr.scale(scaleFactor, scaleFactor)
        cr.translate(-xMin, -yMin)

        for i in range(0, len(self.points)):
            currPoint = self.points[i]
            currX = float(currPoint[0])
            currY = float(currPoint[1])
            nextIndex = i + 1
            if (nextIndex == len(self.points)):
                nextIndex = 0
            nextPoint = self.points[nextIndex]
            nextX = nextPoint[0]
            nextY = nextPoint[1]
            cr.move_to(currX, currY)
            cr.line_to(nextX, nextY)
        cr.restore()
        cr.close_path()
        cr.stroke_preserve()
        return img

    def _expose(self, sender, event, img):
        cr = self.window.cairo_create()
        cr.set_source_surface(img, 0, 0)
        cr.paint()
        return True

if __name__ == '__main__':
    main()

谢谢， IT

如何在DrawingArea上绘制完整的ImageSurface？

0 个答案: