Added a save_as_pdf function

README.md

@@ -4,7 +4,7 @@
 
 ## Plot standard ECG chart from data.
 * Support both direct plotting and plotting SVG preview in browser (currently only works on mac)
-* Support saving PNG and SVG to disk
+* Support saving PNG, JPG, SVG or PDF to disk
 * Support customer defined lead order
 * Support customer defined column count
 
@@ -44,7 +44,7 @@ params:
 import ecg_plot
 
 ecg = load_data() # load data should be implemented by yourself 
-ecg_plot.plot(ecg, sample_rate = 500, title = 'ECG 12')
+ecg_plot.plot(ecg, sample_rate=500, title='ECG 12')
 ecg_plot.show()
 
 ```
@@ -55,7 +55,7 @@ ecg_plot.show()
 import ecg_plot
 
 ecg = load_data() # load data should be implemented by yourself 
-ecg_plot.plot_1(ecg[1], sample_rate=500, title = 'ECG')
+ecg_plot.plot_1(ecg[1], sample_rate=500, title='ECG')
 ecg_plot.show()
 ```
 
@@ -65,8 +65,19 @@ ecg_plot.show()
 import ecg_plot
 
 ecg = load_data() # load data should be implemented by yourself 
-ecg_plot.plot_12(ecg, sample_rate = 500, title = 'ECG 12')
-ecg_plot.save_as_png('example_ecg','tmp/')
+ecg_plot.plot_12(ecg, sample_rate=500, title='ECG 12')
+ecg_plot.save_as_png('example_ecg', 'tmp/')
+
+```
+
+#### Save result as pdf
+
+```
+import ecg_plot
+
+ecg = load_data() # load data should be implemented by yourself 
+fig = ecg_plot.plot_12(ecg, sample_rate = 500, title = 'ECG 12')
+ecg_plot.save_as_pdf('example_ecg', fig, 'tmp/')
 
 ```
 

ecg_plot/__init__.py

@@ -1 +1 @@
-from .ecg_plot import plot_12, plot_1, show, show_svg, save_as_png, save_as_svg, save_as_jpg, plot
+from .ecg_plot import plot_12, plot_1, show, show_svg, save_as_png, save_as_svg, save_as_jpg, save_as_pdf, plot

ecg_plot/ecg_plot.py

@@ -51,6 +51,9 @@ def plot_12(
         speed      : signal speed on display, defaults to 50 mm / sec
         voltage    : signal voltage on display, defaults to 20 mm / mV
         line_width : line width, default to 0.6
+
+    # Returns
+        fig       : figure object
     """
     if not lead_order:
         lead_order = list(range(0,len(ecg)))
@@ -88,6 +91,7 @@ def plot_12(
         t_ax.tick_params(axis='x',rotation=90)
 
         _ax_plot(t_ax, np.arange(0, len(ecg[t_lead])*step, step), ecg[t_lead], seconds)
+    return fig
 
 def plot(
         ecg, 
@@ -116,6 +120,9 @@ def plot(
         show_lead_name : show lead name
         show_grid      : show grid
         show_separate_line  : show separate line
+
+    # Returns
+        fig       : figure object
     """
 
     if not lead_order:
@@ -154,8 +161,25 @@ def plot(
         color_line  = (0,0,0.7)
 
     if(show_grid):
-        ax.set_xticks(np.arange(x_min,x_max,0.2))    
-        ax.set_yticks(np.arange(y_min,y_max,0.5))
+        ax.set_xticks(np.arange(x_min, x_max, 0.2))    
+        ax.set_yticks(np.arange(y_min, y_max, 0.5))
+
+        # Set tick labels only at every 1.0 interval
+        xtick_labels = []
+        for val in np.arange(x_min, x_max, 0.2):
+            if np.isclose(val % 1.0, 0, atol=1e-8):
+                xtick_labels.append(f"{val:g}")
+            else:
+                xtick_labels.append("")
+        ax.set_xticklabels(xtick_labels)
+
+        ytick_labels = []
+        for val in np.arange(y_min, y_max, 0.5):
+            if np.isclose((val - y_min) % 1.0, 0, atol=1e-8):
+                ytick_labels.append(f"{val:g}")
+            else:
+                ytick_labels.append("")
+        ax.set_yticklabels(ytick_labels)
 
         ax.minorticks_on()
 
@@ -193,6 +217,7 @@ def plot(
                     linewidth=line_width * display_factor, 
                     color=color_line
                     )
+    return fig
 
 
 def plot_1(ecg, sample_rate=500, title = 'ECG', fig_width = 15, fig_height = 2, line_w = 0.5, ecg_amp = 1.8, timetick = 0.2):
@@ -203,8 +228,11 @@ def plot_1(ecg, sample_rate=500, title = 'ECG', fig_width = 15, fig_height = 2,
         title      : Title which will be shown on top off chart
         fig_width  : The width of the plot
         fig_height : The height of the plot
+
+    # Returns
+        fig       : figure object
     """
-    plt.figure(figsize=(fig_width,fig_height))
+    fig = plt.figure(figsize=(fig_width,fig_height))
     plt.suptitle(title)
     plt.subplots_adjust(
         hspace = 0, 
@@ -220,6 +248,7 @@ def plot_1(ecg, sample_rate=500, title = 'ECG', fig_width = 15, fig_height = 2,
     #plt.rcParams['lines.linewidth'] = 5
     step = 1.0/sample_rate
     _ax_plot(ax,np.arange(0,len(ecg)*step,step),ecg, seconds, line_w, ecg_amp,timetick)
+    return fig
 
 DEFAULT_PATH = './'
 show_counter = 1
@@ -270,3 +299,15 @@ def save_as_jpg(file_name, path = DEFAULT_PATH):
     plt.ioff()
     plt.savefig(path + file_name + '.jpg')
     plt.close()
+
+def save_as_pdf(file_name, fig, path = DEFAULT_PATH):
+    """Plot multi lead ECG chart.
+    # Arguments
+        file_name: file_name
+        path     : path to save image, defaults to current folder
+    """
+    plt.ioff()
+    fig.savefig(os.path.join(path, file_name + '.pdf'),
+                format='pdf',
+                bbox_inches='tight')
+    plt.close(fig)

ecg_plot_test.py

@@ -23,6 +23,7 @@ def load_ecg_from_mat(file_path):
 
 # ecg_plot.plot(test_ecg, sample_rate = 500, title = '', columns = 1,show_grid = False, show_lead_name = False, style='bw')
 # ecg_plot.plot(test_ecg, sample_rate = 500, title = '', columns = 3)
-ecg_plot.plot(test_ecg, title='test')
+ecg = ecg_plot.plot(test_ecg, title='test')
 ecg_plot.save_as_png('example_ecg_1','tmp/')
+ecg_plot.save_as_pdf('example_ecg_1', ecg,'tmp/')
 ecg_plot.show()