PyGTK 3 (gi.repository) PangoCairo 在绘图文本和线条之间改变颜色

Question

我在 PangoCairo DrawingArea 中更改文本和线条之间的颜色时遇到问题。它们的颜色相同。这是简单的 Python 代码：

from gi.repository import Gtk, Pango, PangoCairo

class Bug(Gtk.DrawingArea):
    def __init__ (self):
        Gtk.DrawingArea.__init__(self)

    def do_draw_cb(self, widget, cr):
        cr.translate ( 10, 10)

        layout = PangoCairo.create_layout (cr)
        desc = Pango.font_description_from_string ("Sans 14")
        layout.set_font_description( desc)
        cr.set_source_rgba(0.0, 1.0, 0.0, 1.0)
        layout.set_text("It is not easy being green", -1 )

        cr.move_to(40, 20)
        cr.line_to(70, 20)
        cr.set_source_rgba(0.0, 0.0, 0.0, 1.0)  # messes up previous set_text
        cr.stroke()
        PangoCairo.show_layout (cr, layout)

def destroy(window):
        Gtk.main_quit()

window = Gtk.Window()
window.set_title ("Green?")

app = Bug()
app.set_size_request (300, 200)

window.add(app)

app.connect('draw', app.do_draw_cb)
window.connect_after('destroy', destroy)
window.show_all()
Gtk.main()

如果我删除第二个 set_source_rgba，那么文本和线条都是绿色而不是黑色。但我想要的是绿色的文字和黑色的线条。我该怎么做呢？

Answer 1

对于布局，调用 show_layout 时会读取颜色，因此第一个 set_source_rgba 没有效果。您应该在设置颜色后立即显示布局。

  def do_draw_cb(self, widget, cr):
      cr.translate ( 10, 10)

      layout = PangoCairo.create_layout (cr)
      desc = Pango.font_description_from_string ("Sans 14")
      layout.set_font_description( desc)
      cr.set_source_rgba(0.0, 1.0, 0.0, 1.0)
      layout.set_text("It is not easy being green", -1 )
      PangoCairo.show_layout (cr, layout)

      cr.move_to(40, 20)
      cr.line_to(70, 20)
      cr.set_source_rgba(0.0, 0.0, 0.0, 1.0)  # messes up previous set_text
      cr.stroke()

PyGTK 3 (gi.repository) PangoCairo 在绘图文本和线条之间改变颜色

PyGTK 3 (gi.repository) PangoCairo changing color between drawing text and line

python

pygobject

gtk3