Add generic label printing demo

generic_label.py

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+from PIL import Image, ImageEnhance, ImageFont, ImageDraw
+import textwrap
+
+text = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.'
+text = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.'
+
+MARGIN = 50
+MAX_W, MAX_H, PAD = 1285 - (MARGIN*2), 635 - (MARGIN*2), 5
+
+im = Image.open('label.png')
+width, height = im.size
+draw = ImageDraw.Draw(im)
+
+def fit_text(text, font_size):
+    font = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf', font_size)
+
+    for cols in range(100, 1, -4):
+        print('trying size', font_size, 'cols', cols)
+
+        paragraph = textwrap.wrap(text, width=cols)
+
+        total_h = -PAD
+        total_w = 0
+
+        for line in paragraph:
+            w, h = draw.textsize(line, font=font)
+            if w > total_w:
+                total_w = w
+            total_h += h + PAD
+
+        if total_w <= MAX_W and total_h < MAX_H:
+            return True, paragraph, total_h
+
+    return False, [], 0
+
+font_size_range = [1, 500]
+
+# Thanks to Alex (UDIA) for the binary search algorithm
+while abs(font_size_range[0] - font_size_range[1]) > 1:
+    font_size = sum(font_size_range) // 2
+    image_fit, check_para, check_h = fit_text(text, font_size)
+    if image_fit:
+        print('Does fit')
+        font_size_range = [font_size, font_size_range[1]]
+        good_size = font_size
+        paragraph = check_para
+        total_h = check_h
+    else:
+        print('Does not fit')
+        font_size_range = [font_size_range[0], font_size]
+
+font = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf', good_size)
+offset = height - MAX_H - MARGIN
+start_h = (MAX_H - total_h) // 2 + offset
+
+current_h = start_h
+for line in paragraph:
+    w, h = draw.textsize(line, font=font)
+    x, y = (MAX_W - w) / 2, current_h
+    draw.text((x+MARGIN, y), line, font=font, fill='black')
+    current_h += h + PAD
+
+
+im.save('tmp.png')
+
+print('Dimentions:', height, width)