Make `plt.{savefig,show}` work fine with dates

plot_statistics.py

@@ -16,8 +16,6 @@ with open('data_keeping_all_blocks_since_last_m_higher_block.json') as f:
     dataKeepingAllBlocksSinceLastMHigherBlock = json.load(f)
 
 fig, targetsAxis = plt.subplots()
-fig.subplots_adjust(right = 0.8)
-fig.subplots_adjust(bottom = 0.4)
 compressedSizeAxis = targetsAxis.twinx()
 compressedScoreAxis = targetsAxis.twinx()
 axes = [targetsAxis, compressedSizeAxis, compressedScoreAxis, targetsAxis.twinx(), compressedScoreAxis, compressedSizeAxis, compressedScoreAxis]
@@ -26,8 +24,6 @@ targets = data['targets']
 
 timestamps = [datetime.datetime.fromtimestamp(timestamp) for timestamp in data['timestamps']]
 
-blockHeights = {timestamp: timestampsIndex for timestampsIndex, timestamp in enumerate(timestamps)}
-
 for x, (target, nextTarget) in enumerate(zip(targets, targets[1:])):
     if nextTarget < target:
         firstTargetDecreaseCurve = plt.axvline(x = timestamps[x], color = 'purple', label = 'first target decrease')
@@ -46,10 +42,18 @@ axesColors = ['blue', 'green', 'brown', 'orange', 'brown', 'red', 'purple']
 axesLabels = ['targets', 'compressed blockchain size (in blocks)', 'compressed blockchain score', 'constant difficulty compressed blockchain size (in blocks)', 'constant difficulty compressed blockchain score', 'compressed blockchain size keeping all blocks since last m higher block (in blocks)', 'compressed blockchain score keeping all blocks since last m higher block']
 axesYValues = [targets, data['compressSize'], data['compressScore'], dataConstantDifficulty['compressSize'], dataConstantDifficulty['compressScore'], dataKeepingAllBlocksSinceLastMHigherBlock['compressSize'], dataKeepingAllBlocksSinceLastMHigherBlock['compressScore']]
 
+blockHeightsCache = {}
+
 class CustomDateFormatter(mdates.ticker.Formatter):
     def __call__(self, x, pos=0):
         datetime_ = mdates.num2date(x)
-        result = datetime_.strftime(f'%m/%Y - {blockHeights[datetime_]}')
+        if not x in blockHeightsCache:
+            for timestampsIndex, timestamp in enumerate(timestamps):
+                if datetime_.timestamp() <= timestamp.timestamp():
+                    blockHeightsCache[x] = timestampsIndex
+                    break
+        blockHeight = f' - {blockHeightsCache[x]}' if x in blockHeightsCache else ''
+        result = datetime_.strftime('%m/%Y') + blockHeight
         return result
 
 plt.gca().xaxis.set_major_formatter(CustomDateFormatter())
@@ -78,9 +82,9 @@ curves.insert(-2, legendNewLine[0])
 curves += legendNewLine + targetRecomputationCurve + [firstTargetDecreaseCurve] + [targetIncreaseCurve]
 labels = [curve.get_label() for curve in curves]
 
-#plt.legend(curves, labels, loc='upper center', framealpha=1, bbox_to_anchor=(0.5, -0.125))
+plt.legend(curves, labels, loc='upper center', framealpha=1, bbox_to_anchor=(0.5, -0.345))
 
-targetsAxis.set_xlabel('Block height')
+targetsAxis.set_xlabel('Block date and height')
 
 for ax, color in zip(axes, axesColors):
     ax.tick_params(axis='y', colors=color)
@@ -88,6 +92,11 @@ for ax, color in zip(axes, axesColors):
 title = 'Variable difficulty Bitcoin compressed blockchain evolution'
 plt.title(title)
 
-plt.show()
+fig.subplots_adjust(top=0.965,
+                    bottom=0.525,
+                    left=0.125,
+                    right=0.8)
+
 fig.set_size_inches((11.2, 7.5), forward=False)
-#plt.savefig(f'{title.lower().replace(" ", "")}.svg')
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+plt.savefig(f'{title.lower().replace(" ", "_")}.svg')
+plt.show()
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