feat: use poppler for image rendering

Author: Dmitry Berezovsky

poetry.lock

@@ -44,6 +44,7 @@ weasyprint="~=60.2"
 pyyaml = ">=5.0.0"
 appdirs = ">=1.4.4"
 jinja2 = ">=3.0.0, <4.0.0"
+python-poppler = "~=0.4.1"
 
 [tool.poetry.dev-dependencies]
 # Dev tools
@@ -103,6 +104,6 @@ follow_imports = "silent"
 ignore_missing_imports = true
 
 [[tool.mypy.overrides]]
-module = ["weasyprint.*", "cli_rack_validation.*", "cli_rack.*", "usb.*", "appdirs.*"]
+module = ["weasyprint.*", "cli_rack_validation.*", "cli_rack.*", "usb.*", "appdirs.*", "poppler.*"]
 ignore_missing_imports = true
 follow_imports = "skip"

pyproject.toml

@@ -20,6 +20,7 @@
 from pathlib import Path
 from typing import Optional
 
+import poppler
 import weasyprint as wp
 from PIL import Image
 from cli_rack.utils import ensure_dir
@@ -44,8 +45,9 @@
 """
 
 PAGE_SIZE_CONFIG_TEMPLATE = """
-@page tape {{
+@page {{
     margin: 0;
+    padding: 0;
     size: {height} {width}; 
 }}
 """
@@ -62,11 +64,14 @@
 
 LOGGER = logging.getLogger("renderer.weasyprint")
 
+DEFAULT_RENDERER_DPI = 96
+
 
 class WeasyprintRenderer(Renderer):
     def __init__(self, template_processor: TemplateProcessor) -> None:
         super().__init__()
         self.template_processor = template_processor
+        self.pdf_page_renderer = poppler.PageRenderer()
 
     def __get_resource_path(self, name: str):
         path = RESOURCES_DIR / name
@@ -127,8 +132,19 @@ def render(self, print_job: PrintJob, tape_params: TapeInfo, is_preview=False, d
             calculated_width_px = self.__find_body_width(rendered_label.pages[0])
             page_config = self.__page_config_css(tape_params, calculated_width_px)
         rendered_label = html.render(stylesheets=stylesheets + [wp.CSS(string=page_config)])
-        result_png = BytesIO()
-        rendered_label.write_png(result_png, resolution=dpi)
+        result_pdf, result_png = BytesIO(), BytesIO()
+        rendered_label.write_pdf(result_pdf, zoom=dpi / DEFAULT_RENDERER_DPI, dpi=dpi)
+        result_pdf.seek(0)
+        pdf = poppler.load(result_pdf)
+        rendered_image = self.pdf_page_renderer.render_page(pdf.create_page(0))
+        pil_image = Image.frombytes(
+            "RGBA",
+            (rendered_image.width, rendered_image.height),
+            rendered_image.data,
+            "raw",
+            str(rendered_image.format),
+        )
+        pil_image.save(result_png, format="png")
         result_png.flush()
         result_png.seek(0)
         self.job_num += 1

src/tapen/renderer/weasyprint.py

@@ -11,7 +11,17 @@ a = Analysis(['src/tapen/cli.py'],
                 ("src/tapen/resources", "tapen/resources"),
                 ("src/tapen/renderer/resources", "tapen/renderer/resources"),
              ],
-             hiddenimports=[],
+             hiddenimports=[
+                "poppler.cpp.embedded_file",
+                "poppler.cpp.toc",
+                "poppler.cpp.font",
+                "poppler.cpp.document",
+                "poppler.cpp.destination",
+                "poppler.cpp.page",
+                "poppler.cpp.page_renderer",
+                "poppler.cpp.version",
+                "poppler.cpp.rectangle",
+             ],
              hookspath=[],
              hooksconfig={},
              runtime_hooks=[],