commit 1d3378762d8282b26b9200cf26a2bedcb0bd4155
author Lei Zhang <thestig@chromium.org> Fri Sep 18 22:59:04 2020 +0000
committer Chromium commit bot <commit-bot@chromium.org> Fri Sep 18 22:59:04 2020 +0000
tree 282918c1b135e4d443faf428f74668f5e80cc34d
parent 2b2e1584ef6ddc352d829848a1433cdd036e965e

Fix FPDFText_GetCharBox() returning excessively tall char boxes.

In CPDF_TextPage::ProcessTextObject(), when the initial char box
calculation produces too small of a char box, the method compensates by
usng the font size for the height, and the glyph width for the width.
The height compensation code uses the font size in the wrong unit, so it
is 1000 times bigger than it needs to be. Fix this and update the
affected test case to show FPDFText_GetCharBox() no longer returns
excessively tall char boxes.

Also update a FPDFText_GetRect() test case that suffers from the same
calculation issue. Now, the second line of hello_world.pdf, which uses a
font of size 16, now has a rectangle height of ~15 instead of ~19.

Bug: pdfium:1591
Change-Id: I1641b882c11c2f06b8a610c9d1ae11c850cd5edf
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/73772
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Hui Yingst <nigi@chromium.org>

core/fpdftext/cpdf_textpage.cpp

diff --git a/core/fpdftext/cpdf_textpage.cpp b/core/fpdftext/cpdf_textpage.cpp
index b355cc9..e138515 100644
--- a/core/fpdftext/cpdf_textpage.cpp
+++ b/core/fpdftext/cpdf_textpage.cpp
@@ -1075,8 +1075,7 @@
     charinfo.m_CharBox.bottom = rect.bottom * fFontSize + item.m_Origin.y;
     if (fabsf(charinfo.m_CharBox.top - charinfo.m_CharBox.bottom) <
         kSizeEpsilon) {
-      charinfo.m_CharBox.top =
-          charinfo.m_CharBox.bottom + pTextObj->GetFontSize();
+      charinfo.m_CharBox.top = charinfo.m_CharBox.bottom + fFontSize;
     }
     if (fabsf(charinfo.m_CharBox.right - charinfo.m_CharBox.left) <
         kSizeEpsilon) {

fpdfsdk/fpdf_text_embeddertest.cpp

diff --git a/fpdfsdk/fpdf_text_embeddertest.cpp b/fpdfsdk/fpdf_text_embeddertest.cpp
index 56b2b27..73754ec 100644
--- a/fpdfsdk/fpdf_text_embeddertest.cpp
+++ b/fpdfsdk/fpdf_text_embeddertest.cpp
@@ -175,7 +175,7 @@
   EXPECT_NEAR(20.847, left, 0.001);
   EXPECT_NEAR(135.167, right, 0.001);
   EXPECT_NEAR(96.655, bottom, 0.001);
-  EXPECT_NEAR(116.000, top, 0.001);
+  EXPECT_NEAR(111.648, top, 0.001);
 
   // Test out of range indicies set outputs to (0.0, 0.0, 0.0, 0.0).
   left = -1.0;
@@ -1643,8 +1643,7 @@
     EXPECT_DOUBLE_EQ(86.0, left);
     EXPECT_DOUBLE_EQ(88.400001525878906, right);
     EXPECT_DOUBLE_EQ(50.0, bottom);
-    // TODO(crbug.com/pdfium/1591): The top value is too big.
-    EXPECT_DOUBLE_EQ(290.0, top);
+    EXPECT_DOUBLE_EQ(50.240001678466797, top);
     ASSERT_TRUE(
         FPDFText_GetCharBox(text_page.get(), 3, &left, &right, &bottom, &top));
     EXPECT_DOUBLE_EQ(86.010002136230469, left);