{"spec_id":"stem-basic","library":"plotnine","language":"python","code":"\"\"\" anyplot.ai\nstem-basic: Basic Stem Plot\nLibrary: plotnine 0.15.7 | Python 3.13.14\nQuality: 90/100 | Updated: 2026-07-25\n\"\"\"\n\nimport os\n\nimport numpy as np\nimport pandas as pd\nfrom plotnine import (\n    aes,\n    element_line,\n    element_rect,\n    element_text,\n    geom_hline,\n    geom_line,\n    geom_point,\n    geom_segment,\n    ggplot,\n    labs,\n    theme,\n    theme_minimal,\n)\n\n\nTHEME = os.getenv(\"ANYPLOT_THEME\", \"light\")\nPAGE_BG = \"#FAF8F1\" if THEME == \"light\" else \"#1A1A17\"\nINK = \"#1A1A17\" if THEME == \"light\" else \"#F0EFE8\"\nINK_SOFT = \"#4A4A44\" if THEME == \"light\" else \"#B8B7B0\"\n\nBRAND = \"#009E73\"\n\n# Data - Damped sinusoidal discrete signal (signal processing example)\nnp.random.seed(42)\nn = 30\nt = np.arange(n)\ndecay = np.exp(-t / 12.0)\nsignal = decay * np.cos(0.55 * t)\n\ndf = pd.DataFrame({\"t\": t, \"signal\": signal, \"zero\": 0.0})\n\n# Fine-resolution decay envelope, plotted as a reference curve so the\n# amplitude decay is visually explicit rather than only implied by the stems.\nt_env = np.linspace(0, n - 1, 200)\nenvelope = pd.DataFrame({\"t\": t_env, \"upper\": np.exp(-t_env / 12.0), \"lower\": -np.exp(-t_env / 12.0)})\n\n# Plot\nplot = (\n    ggplot(df, aes(x=\"t\"))\n    + geom_line(envelope, aes(x=\"t\", y=\"upper\"), color=INK_SOFT, alpha=0.5, linetype=\"dashed\", size=0.6)\n    + geom_line(envelope, aes(x=\"t\", y=\"lower\"), color=INK_SOFT, alpha=0.5, linetype=\"dashed\", size=0.6)\n    + geom_hline(yintercept=0, color=INK_SOFT, size=0.5)\n    + geom_segment(aes(x=\"t\", xend=\"t\", y=\"zero\", yend=\"signal\"), color=BRAND, size=1.0)\n    + geom_point(aes(y=\"signal\"), color=BRAND, size=3.0, stroke=0.5)\n    + labs(x=\"Sample Index\", y=\"Amplitude (normalized)\", title=\"stem-basic · python · plotnine · anyplot.ai\")\n    + theme_minimal()\n    + theme(\n        figure_size=(8, 4.5),\n        plot_background=element_rect(fill=PAGE_BG, color=PAGE_BG),\n        panel_background=element_rect(fill=PAGE_BG),\n        text=element_text(size=7, color=INK),\n        axis_title=element_text(size=10, color=INK),\n        axis_text=element_text(size=8, color=INK_SOFT),\n        plot_title=element_text(size=12, color=INK),\n        panel_grid_major_y=element_line(color=INK, size=0.3, alpha=0.10),\n        panel_grid_major_x=element_line(color=INK, size=0.0, alpha=0.0),\n        panel_grid_minor=element_line(color=INK, size=0.2, alpha=0.05),\n    )\n)\n\n# Save\nplot.save(f\"plot-{THEME}.png\", dpi=400, width=8, height=4.5, units=\"in\", verbose=False)\n"}