Add plumbing for safe printable inset to wptrunner and webdriver.

For print reftests, check <meta name="safe-printable-inset"> to simulate
an unprintable region along the paper edges. The `content` attribute
takes a non-negative number, which is the safe printable inset specified
in centimeters.

Only implemented for executorwebdriver.

Spec discussion: w3c/csswg-drafts#11395
Spec change: w3c/csswg-drafts#13190
RFC: web-platform-tests/rfcs#233

For background, see https://drafts.csswg.org/css-page-3/#printable-area

Author: mstensho

tools/manifest/item.py

@@ -293,10 +293,16 @@ class PrintRefTest(RefTest):
     def page_ranges(self) -> PageRanges:
         return cast(PageRanges, self._extras.get("page_ranges", {}))
 
+    @property
+    def safe_printable_inset(self) -> float:
+        return self._extras.get("safe_printable_inset")
+
     def to_json(self):  # type: ignore
         rv = super().to_json()
         if self.page_ranges:
             rv[-1]["page_ranges"] = self.page_ranges
+        if self.safe_printable_inset:
+            rv[-1]["safe_printable_inset"] = self.safe_printable_inset
         return rv
 
 

tools/manifest/sourcefile.py

@@ -675,6 +675,14 @@ def page_ranges(self) -> Dict[Text, List[List[Optional[int]]]]:
                 rv[key].append(range_parts)
         return rv
 
+    @cached_property
+    def safe_printable_inset(self) -> Optional[float]:
+        """The safe printable inset to simulate (in centimeters)"""
+        for entry in self.root.findall(".//{http://www.w3.org/1999/xhtml}meta[@name='safe-printable-inset']"):
+            key_data, value = self.parse_ref_keyed_meta(entry)
+            return float(value)
+        return None
+
     @cached_property
     def testharness_nodes(self) -> List[ElementTree.Element]:
         """List of ElementTree Elements corresponding to nodes representing a
@@ -1023,6 +1031,7 @@ def manifest_items(self) -> Tuple[Text, List[ManifestItem]]:
                     viewport_size=self.viewport_size,
                     fuzzy=self.fuzzy,
                     page_ranges=self.page_ranges,
+                    safe_printable_inset=self.safe_printable_inset,
                     testdriver=self.has_testdriver,
                 )]
 

tools/webdriver/webdriver/client.py

@@ -791,6 +791,7 @@ def print(
         orientation=None,
         page=None,
         page_ranges=None,
+        safe_printable_inset=None,
         scale=None,
         shrink_to_fit=None,
     ):
@@ -801,6 +802,7 @@ def print(
             "orientation": orientation,
             "page": page,
             "pageRanges": page_ranges,
+            "safePrintableInset": safe_printable_inset,
             "scale": scale,
             "shrinkToFit": shrink_to_fit,
         }.items():

tools/wptrunner/wptrunner/executors/base.py

@@ -418,11 +418,11 @@ def teardown(self):
     def logger(self):
         return self.executor.logger
 
-    def get_hash(self, test, viewport_size, dpi, page_ranges):
+    def get_hash(self, test, viewport_size, dpi, page_ranges, safe_printable_inset):
         key = (test.url, viewport_size, dpi)
 
         if key not in self.screenshot_cache:
-            success, data = self.get_screenshot_list(test, viewport_size, dpi, page_ranges)
+            success, data = self.get_screenshot_list(test, viewport_size, dpi, page_ranges, safe_printable_inset)
 
             if not success:
                 return False, data
@@ -524,9 +524,9 @@ def run_test(self, test):
         viewport_size = test.viewport_size
         dpi = test.dpi
         page_ranges = test.page_ranges
+        safe_printable_inset = test.safe_printable_inset
         self.message = []
 
-
         # Depth-first search of reference tree, with the goal
         # of reachings a leaf node with only pass results
 
@@ -541,7 +541,7 @@ def run_test(self, test):
             fuzzy = self.get_fuzzy(test, nodes, relation)
 
             for i, node in enumerate(nodes):
-                success, data = self.get_hash(node, viewport_size, dpi, page_ranges)
+                success, data = self.get_hash(node, viewport_size, dpi, page_ranges, safe_printable_inset)
                 if success is False:
                     return {"status": data[0], "message": data[1]}
 
@@ -575,7 +575,7 @@ def run_test(self, test):
 
         for i, (node, screenshot) in enumerate(zip(nodes, screenshots)):
             if screenshot is None:
-                success, screenshot = self.retake_screenshot(node, viewport_size, dpi, page_ranges)
+                success, screenshot = self.retake_screenshot(node, viewport_size, dpi, page_ranges, safe_printable_inset)
                 if success:
                     screenshots[i] = screenshot
 
@@ -606,11 +606,12 @@ def get_fuzzy(self, root_test, test_nodes, relation):
                 break
         return value
 
-    def retake_screenshot(self, node, viewport_size, dpi, page_ranges):
+    def retake_screenshot(self, node, viewport_size, dpi, page_ranges, safe_printable_inset):
         success, data = self.get_screenshot_list(node,
                                                  viewport_size,
                                                  dpi,
-                                                 page_ranges)
+                                                 page_ranges,
+                                                 safe_printable_inset)
         if not success:
             return False, data
 
@@ -641,8 +642,8 @@ def get_png_dimensions(
 
         return struct.unpack(">LL", image_data[16:24])
 
-    def get_screenshot_list(self, node, viewport_size, dpi, page_ranges):
-        success, data = self.executor.screenshot(node, viewport_size, dpi, page_ranges)
+    def get_screenshot_list(self, node, viewport_size, dpi, page_ranges, safe_printable_inset):
+        success, data = self.executor.screenshot(node, viewport_size, dpi, page_ranges, safe_printable_inset)
         viewport_size = (800, 600) if viewport_size is None else viewport_size
         dpi = 96 if dpi is None else dpi
         dpcm = dpi / 2.54

tools/wptrunner/wptrunner/executors/executoredge.py

@@ -35,7 +35,7 @@ def setup(self, runner, protocol=None):
         with open(os.path.join(here, "reftest.js")) as f:
             self.script = f.read()
 
-    def screenshot(self, test, viewport_size, dpi, page_ranges):
+    def screenshot(self, test, viewport_size, dpi, page_ranges, safe_printable_inset):
         # https://github.com/web-platform-tests/wpt/issues/7140
         assert dpi is None
 
@@ -62,7 +62,7 @@ def _render(self, protocol, url, timeout):
 
         protocol.base.execute_script(self.wait_script, asynchronous=True)
 
-        pdf = protocol.pdf_print.render_as_pdf(*self.viewport_size)
+        pdf = protocol.pdf_print.render_as_pdf(*self.viewport_size, self.safe_printable_inset)
         screenshots = protocol.pdf_print.pdf_to_png(pdf, self.page_ranges)
         for i, screenshot in enumerate(screenshots):
             # strip off the data:img/png, part of the url

tools/wptrunner/wptrunner/executors/executormarionette.py

@@ -683,7 +683,7 @@ def load_runner(self):
             raise
         self.runner_handle = self.marionette.current_window_handle
 
-    def render_as_pdf(self, width, height):
+    def render_as_pdf(self, width, height, safe_printable_inset):
         margin = 0.5 * 2.54
         body = {
             "page": {
@@ -701,7 +701,7 @@ def render_as_pdf(self, width, height):
         }
         return self.marionette._send_message("WebDriver:Print", body, key="value")
 
-    def pdf_to_png(self, pdf_base64, page_ranges):
+    def pdf_to_png(self, pdf_base64, page_ranges, safe_printable_inset):
         handle = self.marionette.current_window_handle
         _switch_to_window(self.marionette, self.runner_handle)
         try:
@@ -1227,7 +1227,7 @@ def do_test(self, test):
 
         return self.convert_result(test, result)
 
-    def screenshot(self, test, viewport_size, dpi, page_ranges):
+    def screenshot(self, test, viewport_size, dpi, page_ranges, safe_printable_inset):
         # https://github.com/web-platform-tests/wpt/issues/7135
         assert viewport_size is None
         assert dpi is None
@@ -1431,7 +1431,7 @@ def setup(self, runner, protocol=None):
         if not isinstance(self.implementation, InternalRefTestImplementation):
             self.protocol.pdf_print.load_runner()
 
-    def screenshot(self, test, viewport_size, dpi, page_ranges):
+    def screenshot(self, test, viewport_size, dpi, page_ranges, safe_printable_inset):
         # https://github.com/web-platform-tests/wpt/issues/7140
         assert dpi is None
 
@@ -1453,7 +1453,7 @@ def _render(self, protocol, url, timeout):
 
         protocol.base.execute_script(self.wait_script, asynchronous=True)
 
-        pdf = protocol.pdf_print.render_as_pdf(*self.viewport_size)
+        pdf = protocol.pdf_print.render_as_pdf(*self.viewport_size, self.safe_printable_inset)
         screenshots = protocol.pdf_print.pdf_to_png(pdf, self.page_ranges)
         for i, screenshot in enumerate(screenshots):
             # strip off the data:img/png, part of the url

tools/wptrunner/wptrunner/executors/executorselenium.py

@@ -442,7 +442,7 @@ def do_test(self, test):
 
         return self.convert_result(test, result)
 
-    def screenshot(self, test, viewport_size, dpi, page_ranges):
+    def screenshot(self, test, viewport_size, dpi, page_ranges, safe_printable_inset):
         # https://github.com/web-platform-tests/wpt/issues/7135
         assert viewport_size is None
         assert dpi is None

tools/wptrunner/wptrunner/executors/executorservolegacy.py

@@ -244,7 +244,7 @@ def teardown(self):
         os.rmdir(self.tempdir)
         super().teardown()
 
-    def screenshot(self, test, viewport_size, dpi, page_ranges):
+    def screenshot(self, test, viewport_size, dpi, page_ranges, safe_printable_inset):
         with TempFilename(self.tempdir) as output_path:
             extra_args = ["--exit",
                           "--output=%s" % output_path,

tools/wptrunner/wptrunner/executors/executorwebdriver.py

@@ -519,14 +519,15 @@ def load_runner(self):
             raise
         self.runner_handle = self.webdriver.window_handle
 
-    def render_as_pdf(self, width, height):
+    def render_as_pdf(self, width, height, safe_printable_inset_param):
         # All units passed to `print()` are in cm. See [0] for testing specifications.
         #
         # [0]: https://web-platform-tests.org/writing-tests/print-reftests.html
         margin = 0.5 * self.CM_PER_INCH
         pdf_base64 = self.webdriver.print(page={"width": width, "height": height},
                                           margin={"top": margin, "right": margin, "bottom": margin,
                                                   "left": margin},
+                                          safe_printable_inset=safe_printable_inset_param,
                                           background=True,
                                           shrink_to_fit=False)
         return pdf_base64
@@ -1383,7 +1384,7 @@ def do_test(self, test):
 
         return self.convert_result(test, result)
 
-    def screenshot(self, test, viewport_size, dpi, page_ranges):
+    def screenshot(self, test, viewport_size, dpi, page_ranges, safe_printable_inset):
         # https://github.com/web-platform-tests/wpt/issues/7135
         assert viewport_size is None
         assert dpi is None
@@ -1423,7 +1424,7 @@ def setup(self, runner, protocol=None):
         with open(os.path.join(here, "reftest.js")) as f:
             self.script = f.read()
 
-    def screenshot(self, test, viewport_size, dpi, page_ranges):
+    def screenshot(self, test, viewport_size, dpi, page_ranges, safe_printable_inset):
         # https://github.com/web-platform-tests/wpt/issues/7140
         assert dpi is None
 
@@ -1434,6 +1435,7 @@ def screenshot(self, test, viewport_size, dpi, page_ranges):
 
         self.viewport_size = viewport_size
         self.page_ranges = page_ranges.get(test.url)
+        self.safe_printable_inset = safe_printable_inset
         timeout = self.timeout_multiplier * test.timeout if self.debug_info is None else None
         test_url = self.test_url(test)
 
@@ -1449,7 +1451,7 @@ def _render(self, protocol, url, timeout):
         # return value.
         protocol.testdriver.run(url, self.wait_script)
 
-        pdf = protocol.pdf_print.render_as_pdf(*self.viewport_size)
+        pdf = protocol.pdf_print.render_as_pdf(*self.viewport_size, self.safe_printable_inset)
         screenshots = protocol.pdf_print.pdf_to_png(pdf, self.page_ranges)
         for i, screenshot in enumerate(screenshots):
             # strip off the data:img/png, part of the url

tools/wptrunner/wptrunner/executors/protocol.py

@@ -1134,7 +1134,7 @@ class PrintProtocolPart(ProtocolPart):
     name = "pdf_print"
 
     @abstractmethod
-    def render_as_pdf(self, width, height):
+    def render_as_pdf(self, width, height, safe_printable_inset):
         """Output document as PDF"""
         pass