add add_figure for LogWriter (#941)

* add add_figure for LogWriter

* format code

* update date
Co-authored-by: ShenYuhan <yhan_shen@163.com>

demo/components/figure_test.py

+# Copyright (c) 2021 VisualDL Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# =======================================================================
+
+# coding=utf-8
+
+from visualdl import LogWriter
+import numpy as np
+from matplotlib import pyplot as plt
+
+
+if __name__ == '__main__':
+    with LogWriter(logdir="./log/audio_test/train") as writer:
+        x = np.arange(100)
+        y = x ** 2 + 1
+        plt.plot(x, y)
+        fig = plt.gcf()
+        writer.add_figure(tag="figure", figure=fig, step=0)

requirements.txt

@@ -9,3 +9,4 @@ protobuf >= 3.11.0
 requests
 shellcheck-py
 six >= 1.14.0
+matplotlib

visualdl/utils/figure_util.py

+# Copyright (c) 2021 VisualDL Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# =======================================================================
+
+
+def figure_to_image(figures, close=True):
+    """Render matplotlib figure to numpy format.
+
+    Note that this requires the ``matplotlib`` package.
+
+    Args:
+        figure (matplotlib.pyplot.figure) : figure
+        close (bool): Flag to automatically close the figure
+
+    Returns:
+        numpy.array: image in [HWC] order
+    """
+    import numpy as np
+    try:
+        import matplotlib.pyplot as plt
+        import matplotlib.backends.backend_agg as plt_backend_agg
+    except ModuleNotFoundError:
+        print('please install matplotlib')
+
+    def render_to_rgb(figure):
+        canvas = plt_backend_agg.FigureCanvasAgg(figure)
+        canvas.draw()
+        data = np.frombuffer(canvas.buffer_rgba(), dtype=np.uint8)
+        w, h = figure.canvas.get_width_height()
+        image_hwc = data.reshape([h, w, 4])[:, :, 0:3]
+        if close:
+            plt.close(figure)
+        return image_hwc
+
+    image = render_to_rgb(figures)
+    return image

visualdl/writer/writer.py

@@ -19,6 +19,7 @@ import numpy as np
 from visualdl.writer.record_writer import RecordFileWriter
 from visualdl.server.log import logger
 from visualdl.utils.img_util import merge_images
+from visualdl.utils.figure_util import figure_to_image
 from visualdl.component.base_component import scalar, image, embedding, audio, \
     histogram, pr_curve, roc_curve, meta_data, text
 
@@ -192,6 +193,33 @@ class LogWriter(object):
             image(tag=tag, image_array=img, step=step, walltime=walltime,
                   dataformats=dataformats))
 
+    def add_figure(self, tag, figure, step, walltime=None):
+        """Add an figure to vdl record file.
+
+        Args:
+            tag (string): Data identifier
+            figure (matplotlib.figure.Figure): Image represented by a Figure
+            step (int): Step of image
+            walltime (int): Wall time of image
+            dataformats (string): Format of image
+
+        Example:
+            form matplotlib import pyplot as plt
+            import numpy as np
+
+            x = np.arange(100)
+            y = x ** 2 + 1
+            plt.plot(x, y)
+            fig = plt.gcf()
+            writer.add_figure(tag="lll", figure=fig, step=0)
+        """
+        if '%' in tag:
+            raise RuntimeError("% can't appear in tag!")
+        walltime = round(time.time() * 1000) if walltime is None else walltime
+        img = figure_to_image(figure)
+        self._get_file_writer().add_record(
+            image(tag=tag, image_array=img, step=step, walltime=walltime))
+
     def add_text(self, tag, text_string, step=None, walltime=None):
         """Add an text to vdl record file.
         Args: