{"spec_id":"area-cumulative-flow","library":"pygal","language":"python","code":"\"\"\" anyplot.ai\narea-cumulative-flow: Cumulative Flow Diagram for Workflow Analytics\nLibrary: pygal 3.1.3 | Python 3.13.15\nQuality: 93/100 | Updated: 2026-08-18\n\"\"\"\n\nimport os\n\nimport cairosvg\nimport numpy as np\nimport pandas as pd\nimport pygal\nfrom pygal.style import Style\n\n\n# pygal drops its internal layout state after render() unless this is set —\n# the QA-crunch annotation below needs chart.view/chart.margin_box afterwards\n# to place the callout at the exact pixel position of the widened Testing band.\nos.environ[\"PYGAL_KEEP_STATE\"] = \"1\"\n\n# Theme tokens\nTHEME = os.getenv(\"ANYPLOT_THEME\", \"light\")\nPAGE_BG = \"#FAF8F1\" if THEME == \"light\" else \"#1A1A17\"\nINK = \"#1A1A17\" if THEME == \"light\" else \"#F0EFE8\"\nINK_MUTED = \"#6B6A63\" if THEME == \"light\" else \"#A8A79F\"\n\nIMPRINT = (\"#009E73\", \"#C475FD\", \"#4467A3\", \"#BD8233\", \"#AE3030\")\n\n# Data: 90-day Kanban board for a software delivery team\nnp.random.seed(42)\nn_days = 90\ndates = pd.date_range(\"2024-01-02\", periods=n_days, freq=\"D\")\n\n# Daily new items entering the backlog (1–3 per day)\ndaily_new = np.random.randint(1, 4, n_days)\nbacklog_entered = np.cumsum(daily_new).astype(float)\n\n# Each stage has a lag from the previous stage boundary. Testing capacity\n# tightens during a mid-period bottleneck (QA understaffed vs. dev throughput),\n# so items linger longer in Development before Testing can absorb them. The\n# lag ramps by at most 1 day/day so the cumulative counts stay non-decreasing.\nanalysis_lag = 4 # days after entering backlog before analysis starts\ndev_lag = 8 # days in analysis before development starts\ntesting_lag_normal = 10 # days in development before testing starts (baseline)\ntesting_lag_bottleneck = 22 # days during the QA capacity crunch (peak)\ndone_lag = 6 # days in testing before done\n\nramp = np.arange(testing_lag_normal, testing_lag_bottleneck + 1)\ntesting_lag_schedule = np.concatenate(\n [\n np.full(30, testing_lag_normal), # normal flow\n ramp, # QA backlog builds up\n np.full(14, testing_lag_bottleneck), # crunch plateau\n ramp[::-1], # extra QA capacity drains the backlog\n ]\n)\ntesting_lag_schedule = np.concatenate(\n [testing_lag_schedule, np.full(n_days - len(testing_lag_schedule), testing_lag_normal)]\n)\n\nanalysis_entered = np.zeros(n_days)\ndev_entered = np.zeros(n_days)\ntesting_entered = np.zeros(n_days)\ndone = np.zeros(n_days)\n\nfor d in range(n_days):\n if d - analysis_lag >= 0:\n analysis_entered[d] = backlog_entered[d - analysis_lag]\n if d - dev_lag >= 0:\n dev_entered[d] = analysis_entered[d - dev_lag]\n lag = testing_lag_schedule[d]\n if d - lag >= 0:\n testing_entered[d] = dev_entered[d - lag]\n if d - done_lag >= 0:\n done[d] = testing_entered[d - done_lag]\n\n# Band widths (WIP per stage) — stacked bottom-to-top: Done → Backlog\ndone_band = done\ntesting_band = testing_entered - done\ndev_band = dev_entered - testing_entered\nanalysis_band = analysis_entered - dev_entered\nbacklog_band = backlog_entered - analysis_entered\n\n# X-axis labels — show every 15th day\nall_labels = [d.strftime(\"%b %d\") for d in dates]\nmajor_labels = [d.strftime(\"%b %d\") for d in dates[::15]]\n\n# Style\ncustom_style = Style(\n background=PAGE_BG,\n plot_background=PAGE_BG,\n foreground=INK,\n foreground_strong=INK,\n foreground_subtle=INK_MUTED,\n colors=IMPRINT,\n title_font_size=66,\n label_font_size=56,\n major_label_font_size=44,\n legend_font_size=44,\n value_font_size=36,\n stroke_width=3,\n)\n\n# Chart\nchart = pygal.StackedLine(\n style=custom_style,\n fill=True,\n width=3200,\n height=1800,\n title=\"area-cumulative-flow · python · pygal · anyplot.ai\",\n x_title=\"Date\",\n y_title=\"Cumulative Item Count\",\n show_minor_x_labels=False,\n x_label_rotation=30,\n margin=80,\n show_dots=False,\n legend_at_bottom=True,\n legend_at_bottom_columns=5,\n legend_box_size=32,\n spacing=24,\n)\n\nchart.x_labels = all_labels\nchart.x_labels_major = major_labels\n\n# Add series from bottom (Done) to top (Backlog) — workflow order reversed.\n# Testing (the QA-bottleneck stage) gets a bolder boundary stroke than the\n# other bands: an intentional visual hierarchy that draws the eye straight\n# to the widening band instead of leaving every stage equally weighted.\nchart.add(\"Done\", done_band.tolist())\nchart.add(\"Testing\", testing_band.tolist(), stroke_style={\"width\": 6})\nchart.add(\"Development\", dev_band.tolist())\nchart.add(\"Analysis\", analysis_band.tolist())\nchart.add(\"Backlog\", backlog_band.tolist())\n\n# Render once, keeping pygal's internal view/margin state (see\n# PYGAL_KEEP_STATE above) so the QA-crunch callout below can be placed at\n# the exact pixel position of the Testing band's widest point.\nsvg = chart.render()\nsvg_text = svg.decode(\"utf-8\") if isinstance(svg, bytes) else svg\n\n# Annotate the QA-capacity crunch: the day the Testing band is widest.\npeak_day = int(np.argmax(testing_band))\nanchor_value = (done[peak_day] + testing_entered[peak_day]) / 2\nanchor_xf = peak_day / (n_days - 1)\nanchor_x = chart.margin_box.left + chart.view.x(anchor_xf)\nanchor_y = chart.margin_box.top + chart.view.y(anchor_value)\n\n# Callout box sits in the empty canvas above the pre-crunch ramp-up (offsets\n# tuned for this fixed-seed dataset so the box and its leader line never\n# cross into the filled bands).\nbox_w, box_h = 520, 118\nbox_right = anchor_x - 150\nbox_left = box_right - box_w\nbox_bottom = anchor_y - 434\nbox_top = box_bottom - box_h\ntext_x = (box_left + box_right) / 2\ntext_y = box_top + box_h / 2 + 13\n\nannotation = f\"\"\"\n\n \n \n \n QA capacity crunch\n\n\"\"\"\nsvg_text = svg_text.replace(\"\", annotation + \"\", 1)\n\n# Save\nwith open(f\"plot-{THEME}.html\", \"wb\") as f:\n f.write(svg_text.encode(\"utf-8\"))\ncairosvg.svg2png(bytestring=svg_text.encode(\"utf-8\"), write_to=f\"plot-{THEME}.png\", dpi=72)\n"}