Wxpython 简明教程

wxPython - Drawing API

GDI + （图形绘制界面）、 CoreGraphics 和 Cairo libraries 构成了 wxPython 中绘制 API 的框架。wx.GraphicsContext 是主要的绘图对象，使用它可以创建各种设备上下文对象。

GDI+ (Graphics Drawing Interface), CoreGraphics and Cairo libraries form the framework of drawing API in wxPython. wx.GraphicsContext is the primary drawable object, using which various Device Context objects are created.

wx.DC 是一个抽象类。它的派生类用于在不同设备上渲染图形和文本。设备上下文类为 -

wx.DC is an abstract class. Its derived classes are used to render graphics and text on different devices. The Device Context classes are −

  1. wx.ScreenDC − Use this to paint on the screen, as opposed to an individual window.

  2. wx.ClientDC − Use this to paint on the client area of the window (the part without borders and other decorations), but do not use it from within an wxPaintEvent.

  3. wx.PaintDC − Use this to paint on the client area of the window, but only from within a wxPaintEvent.

  4. wx.WindowDC − Use this to paint on the whole area of the window, including decorations. This may not be available on non-Windows platforms.

wxPython 绘图 API 提供用于绘制形状、文本和图像的不同函数。用于绘制目的的对象（比如颜色、笔、画笔和字体）也可以使用 GDI 类进行构建。

Drawing API of wxPython offers different functions for drawing shape, text and image. Objects required for drawing purpose, like Colour, Pen, Brush and Font can also be constructed using GDI classes.

wx.Colour Class

Color 对象表示 RGB（红、绿和蓝）强度值的组合，每个都在 0-255 的范围内。有一些预定义的颜色对象，例如：

Colour object represents combination of RGB (RED, Green and Blue) intensity values, each on the scale of 0-255. There are a few predefined colour objects like −

  1. wxBLACK

  2. wxBLUE

  3. wxCYAN

  4. wxGREEN

  5. wxYELLOW

  6. wxLIGHT_GREY

  7. wxRED

  8. wxWHITE

以 RGB 值自定义组合形成颜色 为 wx.Colour object 。

Color with custom combination of RGB values is formed as wx.Colour object.

wx.Colour(r,g,b)

wx.Pen Class

Pen 对象决定图形形状的颜色、宽度和样式，如线、矩形、圆形等。

Pen object determines the colour, width and style of the shape of graphics like line, rectangle, circle etc.

Predefined Pen objects 为：

Predefined Pen objects are −

wxBLACK_DASHED_PEN

wxBLACK_PEN

wxBLUE_PEN

wxCYAN_PEN

wxGREEN_PEN

wxYELLOW_PEN

wxGREY_PEN

wxLIGHT_GREY_PEN

wxMEDIUM_GREY_PEN

wxRED_PEN

wxTRANSPARENT_PEN

wxWHITE_PEN

Predefined Pen styles 为：

Predefined Pen styles are −

wx.SOLID

wx.DOT

wx.LONG_DASH

wx.SHORT_DASH

wx.DOT_DASH

wx.TRANSPARENT

wx.Brush Class

Brush 是另一个基本图形对象，用于填充矩形、椭圆、圆形等形状的背景。

Brush is another elementary graphics object required to fill the backgrounds of shapes such as rectangle, ellipse, circle etc.

自定义 Brush 对象需要 wx.Color 和画笔样式参数。以下是预定义画笔样式的列表：

A custom Brush object requires wx.Colour and Brush style parameters. The following is a list of predefined brush styles −

wx.SOLID

wx.STIPPLE

wx.BDIAGONAL_HATCH

wx.CROSSDIAG_HATCH

wx.FDIAGONAL_HATCH

wx.CROSS_HATCH

wx.HORIZONTAL_HATCH

wx.VERTICAL_HATCH

wx.TRANSPARENT

wxPython 具有很多便于绘制不同形状、文本和图像的函数。

wxPython has a number of functions that facilitate drawing different shapes, text and image.

S.N.

Functions & Description

1

DrawRectangle() Draws a rectangle of given dimensions

2

DrawCircle() Draws a circle at the given point as center and radius

3

DrawEllipse() Draws an ellipse with the given x and y radius

4

DrawLine() Draws a line beween two wx.Point objects

5

DrawBitmap() Draw an image at the given position

6

DrawText() Displays the given text at the specified position

Example

上述函数在以下示例中实现，利用了 Pen、Brush、Colour 和 Font 对象。

The above functions are implemented in the following example, making use of Pen, Brush, Colour and Font objects.

完整代码如下所示：

The complete code is as follows −

import wx

class Mywin(wx.Frame):

   def __init__(self, parent, title):
      super(Mywin, self).__init__(parent, title = title,size = (500,300))
      self.InitUI()

   def InitUI(self):
      self.Bind(wx.EVT_PAINT, self.OnPaint)
      self.Centre()
      self.Show(True)

   def OnPaint(self, e):
      dc = wx.PaintDC(self)
      brush = wx.Brush("white")
      dc.SetBackground(brush)
      dc.Clear()

      dc.DrawBitmap(wx.Bitmap("python.jpg"),10,10,True)
      color = wx.Colour(255,0,0)
      b = wx.Brush(color)

      dc.SetBrush(b)
      dc.DrawCircle(300,125,50)
      dc.SetBrush(wx.Brush(wx.Colour(255,255,255)))
      dc.DrawCircle(300,125,30)

      font = wx.Font(18, wx.ROMAN, wx.ITALIC, wx.NORMAL)
      dc.SetFont(font)
      dc.DrawText("Hello wxPython",200,10)

      pen = wx.Pen(wx.Colour(0,0,255))
      dc.SetPen(pen)
      dc.DrawLine(200,50,350,50)
      dc.SetBrush(wx.Brush(wx.Colour(0,255,0), wx.CROSS_HATCH))
      dc.DrawRectangle(380, 15, 90, 60)

ex = wx.App()
Mywin(None,'Drawing demo')
ex.MainLoop()

上述代码生成以下输出 -

The above code produces the following output −

drawing demo