CairoError: CAIRO_STATUS_INVALID_MATRIX

[lilydjwg]

WeasyPrint raises CairoError with the following HTML document (the background image must exist):

<style type="text/css">
  div {
    background-image: url("t.png");
    display: inline-block;
    background-size: cover;
  }
</style>
<div></div>

The error is:

Traceback (most recent call last):
  File ".../venv/bin/weasyprint", line 9, in <module>
    load_entry_point('WeasyPrint==0.22', 'console_scripts', 'weasyprint')()
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/__main__.py", line 156, in main
    getattr(html, 'write_' + format_)(output, **kwargs)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/__init__.py", line 200, in write_png
    .write_png(target, resolution))
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/document.py", line 543, in write_png
    surface, max_width, sum_heights = self.write_image_surface(resolution)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/document.py", line 518, in write_image_surface
    page.paint(context, pos_x, pos_y, scale=dppx, clip=True)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/document.py", line 241, in paint
    draw_page(self._page_box, cairo_context, self._enable_hinting)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/draw.py", line 102, in draw_page
    draw_stacking_context(context, stacking_context, enable_hinting)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/draw.py", line 216, in draw_stacking_context
    draw_stacking_context(context, child_context, enable_hinting)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/draw.py", line 212, in draw_stacking_context
    enable_hinting)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/draw.py", line 843, in draw_inline_level
    draw_inline_level(context, page, child, enable_hinting)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/draw.py", line 834, in draw_inline_level
    draw_stacking_context(context, stacking_context, enable_hinting)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/draw.py", line 168, in draw_stacking_context
    context, stacking_context.page, box, enable_hinting)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/draw.py", line 106, in draw_box_background_and_border
    draw_background(context, box.background, enable_hinting)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/draw.py", line 302, in draw_background
    draw_background_image(context, layer, bg.image_rendering)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/draw.py", line 349, in draw_background_image
    layer.image.draw(sub_context, image_width, image_height, image_rendering)
  File ".../venv/local/lib/python2.7/site-packages/weasyprint/images.py", line 81, in draw
    concrete_height / self._intrinsic_height)
  File ".../venv/local/lib/python2.7/site-packages/cairocffi/context.py", line 707, in scale
    self._check_status()
  File ".../venv/local/lib/python2.7/site-packages/cairocffi/context.py", line 108, in _check_status
    _check_status(cairo.cairo_status(self._pointer))
  File ".../venv/local/lib/python2.7/site-packages/cairocffi/__init__.py", line 68, in _check_status
    raise exception(message, status)
cairocffi.CairoError: cairo returned CAIRO_STATUS_INVALID_MATRIX: invalid matrix (not invertible)

In images.py, RasterImage.draw, concrete_width and concrete_height both are zeros.

[SimonSapin]

Does this happen with any image, or only this particular t.png image? If the latter, could you provide the image?

[lilydjwg]

Any image. I've tried several, they all cause the error. Try my avatar on the left if you can't find one :-)

[SimonSapin]

Thanks for the bug report! Version 0.23 is on PyPI and includes the fix for this.