from __future__ import with_statement

from enthought.traits.api import Float

from enthought.enable.api import AbstractOverlay, Canvas, Viewport, \
        Window, ColorTrait, Scrolled, Container
from enthought.enable.tools.api import ViewportPanTool
from enthought.enable.example_support import demo_main, DemoFrame


class EventTracer(AbstractOverlay):
    """ Draws a marker under the mouse cursor where an event is occurring. """
    
    x = Float
    y = Float

    color = ColorTrait("red")
    size = Float(5)
    angle = Float(0.0)   # angle in degrees

    def normal_mouse_move(self, event):
        self.x = event.x
        self.y = event.y
        self.component.request_redraw()

    def overlay(self, component, gc, view_bounds, mode):
        with gc:
            gc.translate_ctm(self.x, self.y)
            if self.angle != 0:
                gc.rotate_ctm(self.angle * 3.14159/180.)
            gc.set_stroke_color(self.color_)
            gc.set_line_width(1.0)
            gc.move_to(-self.size, 0)
            gc.line_to(self.size, 0)
            gc.move_to(0, -self.size)
            gc.line_to(0, self.size)
            gc.stroke_path()


class MyFrame(DemoFrame):

    def _create_window(self):

        canvas = Canvas(bgcolor="lightsteelblue", draw_axes=True)
        canvas.overlays.append(EventTracer(canvas, color="green", size=8,
                                           angle=45.0))

        viewport = Viewport(component=canvas, enable_zoom=True)
        viewport.view_position = [0,0]
        viewport.tools.append(ViewportPanTool(viewport, drag_button="right"))
        viewport.overlays.append(EventTracer(viewport))

        if 1:
            scrolled = Scrolled(canvas, inside_padding_width = 0,
                            mousewheel_scroll = False,
                            viewport_component = viewport,
                            always_show_sb = True,
                            continuous_drag_update = True)
            return Window(self, -1, component=scrolled)

        elif 1:
            viewport.bounds = [300, 300]
            viewport.position = [10,10]
            container = Container(fit_window=True, auto_size=False,
                                  border_visible=True,
                                  border_color = "blue")
            container.padding = 20
            container.add(viewport)
            return Window(self, -1, component=container)
        
        else:
            return Window(self, -1, component=viewport)

if __name__ == "__main__":
    demo_main(MyFrame, title="Canvas example")