fix(render): viewport not set when only one dimension specified — causes 2x width in generated images

[CompilError-bts]

Summary

Summary by Sourcery

Bug Fixes:

• Fix incorrect viewport handling when only one dimension (width or height) is specified, preventing incorrectly scaled generated images.

[sourcery-ai]

Hey - I've found 1 issue, and left some high level feedback:

• Now that set_viewport_size is called unconditionally, the behavior also changes for the case where both viewport_width and viewport_height are None; consider adding a short comment above this block to explicitly document that we intentionally always set a viewport (using 800x720 defaults) rather than relying on Playwright’s default.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Now that `set_viewport_size` is called unconditionally, the behavior also changes for the case where both `viewport_width` and `viewport_height` are `None`; consider adding a short comment above this block to explicitly document that we intentionally always set a viewport (using 800x720 defaults) rather than relying on Playwright’s default.

## Individual Comments

### Comment 1
<location path="src/render.py" line_range="241-242" />
<code_context>
         # Set viewport size if either width or height is specified
-        if viewport_width is not None and viewport_height is not None:
-            # Default values if one dimension not specified
-            await page.set_viewport_size({"width": width, "height": height})
-            logger.info(f"html2pic: set viewport size to {width}x{height}")
+        # Default values if one dimension not specified
+        await page.set_viewport_size({"width": width, "height": height})
</code_context>
<issue_to_address>
**question (bug_risk):** Consider whether forcing a default viewport even when no dimensions are provided changes existing behavior unintentionally.

Previously, the viewport was only set when both dimensions were provided; now it’s always set to 800×720, even when both are `None`. This could break callers that relied on the browser’s default. If that change isn’t intentional, consider guarding with something like `if viewport_width is not None or viewport_height is not None:` so the default is only applied when at least one dimension is specified.
</issue_to_address>

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[sourcery-ai]

question (bug_risk): Consider whether forcing a default viewport even when no dimensions are provided changes existing behavior unintentionally.

Previously, the viewport was only set when both dimensions were provided; now it’s always set to 800×720, even when both are None. This could break callers that relied on the browser’s default. If that change isn’t intentional, consider guarding with something like if viewport_width is not None or viewport_height is not None: so the default is only applied when at least one dimension is specified.

[gemini-code-assist]

Code Review

This pull request modifies the html2pic function in src/render.py to set the viewport size unconditionally, ensuring default dimensions are applied when overrides are not provided. Feedback was provided to update the surrounding comments, as the removal of the conditional logic rendered the existing documentation misleading or redundant.

[gemini-code-assist]

The comments in this block are now misleading because the if condition was removed, meaning the viewport is now set unconditionally. The comment on line 239 is redundant as the default logic is already handled in lines 236-237. Furthermore, the comment on line 238 (which is a context line in this diff) now contradicts the implementation as it states the viewport is only set if a dimension is specified. Consider updating the comments to accurately reflect that the viewport is now always set to ensure the library's default dimensions (800x720) are applied when no overrides are provided.

Suggested change

	# Default values if one dimension not specified
	await page.set_viewport_size({"width": width, "height": height})
	logger.info(f"html2pic: set viewport size to {width}x{height}")
	# Set viewport size using specified values or defaults
	await page.set_viewport_size({"width": width, "height": height})
	logger.info(f"html2pic: set viewport size to {width}x{height}")