matplotlib & pandas

Python/matplotlab/gallery/user_interfaces/canvasagg.md

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+# CanvasAgg演示
+
+此示例展示了如何直接使用AGG后端创建图像，对于希望完全控制其代码而不使用pylot界面来管理图形、图形关闭等的Web应用程序开发人员来说，这可能是有用的。
+
+**注意：**没有必要避免使用图形前端 - 只需将后端设置为“Agg”就足够了。
+
+在这个例子中，我们展示了如何将画布的内容保存到文件，以及如何将它们提取到一个字符串，该字符串可以传递给PIL或放在一个numpy数组中。 后一种功能允许例如使用没有文档到磁盘的cp脚本。
+
+```python
+from matplotlib.backends.backend_agg import FigureCanvasAgg
+from matplotlib.figure import Figure
+import numpy as np
+
+fig = Figure(figsize=(5, 4), dpi=100)
+# A canvas must be manually attached to the figure (pyplot would automatically
+# do it).  This is done by instantiating the canvas with the figure as
+# argument.
+canvas = FigureCanvasAgg(fig)
+
+# Do some plotting.
+ax = fig.add_subplot(111)
+ax.plot([1, 2, 3])
+
+# Option 1: Save the figure to a file; can also be a file-like object (BytesIO,
+# etc.).
+fig.savefig("test.png")
+
+# Option 2: Save the figure to a string.
+canvas.draw()
+s, (width, height) = canvas.print_to_buffer()
+
+# Option 2a: Convert to a NumPy array.
+X = np.fromstring(s, np.uint8).reshape((height, width, 4))
+
+# Option 2b: Pass off to PIL.
+from PIL import Image
+im = Image.frombytes("RGBA", (width, height), s)
+
+# Uncomment this line to display the image using ImageMagick's `display` tool.
+# im.show()
+```
+
+## 参考
+
+此示例中显示了以下函数，方法，类和模块的使用：
+
+```python
+import matplotlib
+matplotlib.backends.backend_agg.FigureCanvasAgg
+matplotlib.figure.Figure
+matplotlib.figure.Figure.add_subplot
+matplotlib.figure.Figure.savefig
+matplotlib.axes.Axes.plot
+```
+
+## 下载这个示例
+            
+- [下载python源码: canvasagg.py](https://matplotlib.org/_downloads/canvasagg.py)
+- [下载Jupyter notebook: canvasagg.ipynb](https://matplotlib.org/_downloads/canvasagg.ipynb)