From 42ff7fc84289a885c86d4629ebcf8dd9a65cef2d Mon Sep 17 00:00:00 2001
From: "James R. Barlow" <james@purplerock.ca>
Date: Mon, 12 Feb 2024 01:32:26 -0800
Subject: [PATCH] Fix handling of pages that are restored to correct
 orientation with /Rotate

Appears inversion of CTM was incorrect, introduced in commit 9898904
---
 src/ocrmypdf/_graft.py |  5 ++-
 tests/test_optimize.py |  7 ++--
 tests/test_rotation.py | 76 +++++++++++++++++++++++++++++-------------
 3 files changed, 58 insertions(+), 30 deletions(-)

diff --git a/src/ocrmypdf/_graft.py b/src/ocrmypdf/_graft.py
index 481f029c..1848e884 100644
--- a/src/ocrmypdf/_graft.py
+++ b/src/ocrmypdf/_graft.py
@@ -289,9 +289,8 @@ class OcrGrafter:
 
             # Translate the text so it is centered at (0, 0), rotate it there, adjust
             # for a size different between initial and text PDF, then untranslate, and
-            # finally move the lower left corner to match the mediabox. All transforms
-            # must be premultiplied so they are applied in reverse order here.
-            ctm = corner @ untranslate @ scale @ rotate @ translate
+            # finally move the lower left corner to match the mediabox.
+            ctm = translate @ rotate @ scale @ untranslate @ corner
             log.debug("Grafting with ctm %r", ctm)
 
             base_resources = _ensure_dictionary(base_page.obj, Name.Resources)
diff --git a/tests/test_optimize.py b/tests/test_optimize.py
index 69cdfcc2..4ba136bf 100644
--- a/tests/test_optimize.py
+++ b/tests/test_optimize.py
@@ -176,9 +176,10 @@ def test_multiple_pngs(resources, outdir):
         )
         mock.assert_called()
 
-    with pikepdf.open(outdir / 'in.pdf') as inpdf, pikepdf.open(
-        outdir / 'out.pdf'
-    ) as outpdf:
+    with (
+        pikepdf.open(outdir / 'in.pdf') as inpdf,
+        pikepdf.open(outdir / 'out.pdf') as outpdf,
+    ):
         for n in range(len(inpdf.pages)):
             inim = next(iter(inpdf.pages[n].images.values()))
             outim = next(iter(outpdf.pages[n].images.values()))
diff --git a/tests/test_rotation.py b/tests/test_rotation.py
index 47443c4c..b5e4ffbd 100644
--- a/tests/test_rotation.py
+++ b/tests/test_rotation.py
@@ -211,34 +211,35 @@ def test_rotate_deskew_ocr_timeout(resources, outdir):
     assert cmp > 0.95
 
 
+def make_rotate_test(imagefile, outdir, prefix, image_angle, page_angle):
+    memimg = BytesIO()
+    with Image.open(fspath(imagefile)) as im:
+        if image_angle != 0:
+            ccw_angle = -image_angle % 360
+            im = im.transpose(getattr(Image.Transpose, f'ROTATE_{ccw_angle}'))
+        im.save(memimg, format='PNG')
+    memimg.seek(0)
+    mempdf = BytesIO()
+    img2pdf.convert(
+        memimg.read(),
+        layout_fun=img2pdf.get_fixed_dpi_layout_fun((200, 200)),
+        outputstream=mempdf,
+        **IMG2PDF_KWARGS,
+    )
+    mempdf.seek(0)
+    with pikepdf.open(mempdf) as pdf:
+        pdf.pages[0].Rotate = page_angle
+        target = outdir / f'{prefix}_{image_angle}_{page_angle}.pdf'
+        pdf.save(target)
+        return target
+
+
 @pytest.mark.slow
 @pytest.mark.parametrize('page_angle', (0, 90, 180, 270))
 @pytest.mark.parametrize('image_angle', (0, 90, 180, 270))
 def test_rotate_page_level(image_angle, page_angle, resources, outdir, caplog):
-    def make_rotate_test(prefix, image_angle, page_angle):
-        memimg = BytesIO()
-        with Image.open(fspath(resources / 'typewriter.png')) as im:
-            if image_angle != 0:
-                ccw_angle = -image_angle % 360
-                im = im.transpose(getattr(Image.Transpose, f'ROTATE_{ccw_angle}'))
-            im.save(memimg, format='PNG')
-        memimg.seek(0)
-        mempdf = BytesIO()
-        img2pdf.convert(
-            memimg.read(),
-            layout_fun=img2pdf.get_fixed_dpi_layout_fun((200, 200)),
-            outputstream=mempdf,
-            **IMG2PDF_KWARGS,
-        )
-        mempdf.seek(0)
-        with pikepdf.open(mempdf) as pdf:
-            pdf.pages[0].Rotate = page_angle
-            target = outdir / f'{prefix}_{image_angle}_{page_angle}.pdf'
-            pdf.save(target)
-            return target
-
-    reference = make_rotate_test('ref', 0, 0)
-    test = make_rotate_test('test', image_angle, page_angle)
+    reference = make_rotate_test(resources / 'typewriter.png', outdir, 'ref', 0, 0)
+    test = make_rotate_test(resources, outdir, 'test', image_angle, page_angle)
     out = test.with_suffix('.out.pdf')
 
     exitcode = run_ocrmypdf_api(
@@ -254,6 +255,33 @@ def test_rotate_page_level(image_angle, page_angle, resources, outdir, caplog):
     assert compare_images_monochrome(outdir, reference, 1, out, 1) > 0.2
 
 
+@pytest.mark.slow
+@pytest.mark.parametrize('page_rotate_angle', (0, 90, 180, 270))
+def test_page_rotate_tag(page_rotate_angle, resources, outdir, caplog):
+    # Check that pages that have an image that is misrotated but restored to
+    # correct rotation with a /Rotate will be processed correct and yield text.
+    test = make_rotate_test(
+        resources / 'crom.png', outdir, 'test', -page_rotate_angle, page_rotate_angle
+    )
+    out = test.with_suffix('.out.pdf')
+    exitcode = run_ocrmypdf_api(
+        test,
+        out,
+        '-O0',
+    )
+    assert exitcode == 0, caplog.text
+
+    def pdftotext(filename):
+        return (
+            run(['pdftotext', '-enc', 'UTF-8', filename, '-'], capture_output=True)
+            .stdout.strip()
+            .decode('utf-8')
+        )
+
+    test_text = pdftotext(out)
+    assert 'is a' in test_text, test_text
+
+
 def test_rasterize_rotates(resources, tmp_path):
     pm = get_plugin_manager([])