API and test for retrieving metadata from image objects

Added FPDFImageObj_GetImageMetadata() for retriving the image metadata
of image objects, including its dimension, DPI, bits per pixel, and
colorspace.
    * Added a corresponding embedder test.

Bug=pdfium:677

Change-Id: I4229334d1ac2125b21a46e2e44ea937ea2e94b51
Reviewed-on: https://pdfium-review.googlesource.com/10110
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Jane Liu <janeliulwq@google.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/fpdfsdk/fpdfedit_embeddertest.cpp b/fpdfsdk/fpdfedit_embeddertest.cpp
index e62ef2149b..6dc177e2b5 100644
--- a/fpdfsdk/fpdfedit_embeddertest.cpp
+++ b/fpdfsdk/fpdfedit_embeddertest.cpp
@@ -1084,3 +1084,50 @@ TEST_F(FPDFEditEmbeddertest, GetImageFilters) {
 
   UnloadPage(page);
 }
+
+TEST_F(FPDFEditEmbeddertest, GetImageMetadata) {
+  ASSERT_TRUE(OpenDocument("embedded_images.pdf"));
+  FPDF_PAGE page = LoadPage(0);
+  ASSERT_TRUE(page);
+
+  // Check that getting the metadata of a null object would fail.
+  FPDF_IMAGEOBJ_METADATA metadata;
+  EXPECT_FALSE(FPDFImageObj_GetImageMetadata(nullptr, page, &metadata));
+
+  // Check that receiving the metadata with a null metadata object would fail.
+  FPDF_PAGEOBJECT obj = FPDFPage_GetObject(page, 35);
+  EXPECT_FALSE(FPDFImageObj_GetImageMetadata(obj, page, nullptr));
+
+  // Check that when retrieving an image object's metadata without passing in
+  // |page|, all values are correct, with the last two being default values.
+  ASSERT_EQ(FPDF_PAGEOBJ_IMAGE, FPDFPageObj_GetType(obj));
+  ASSERT_TRUE(FPDFImageObj_GetImageMetadata(obj, nullptr, &metadata));
+  EXPECT_EQ(92u, metadata.width);
+  EXPECT_EQ(68u, metadata.height);
+  EXPECT_NEAR(96.000000, metadata.horizontal_dpi, 0.001);
+  EXPECT_NEAR(96.000000, metadata.vertical_dpi, 0.001);
+  EXPECT_EQ(0u, metadata.bits_per_pixel);
+  EXPECT_EQ(FPDF_COLORSPACE_UNKNOWN, metadata.colorspace);
+
+  // Verify the metadata of a bitmap image with indexed colorspace.
+  ASSERT_TRUE(FPDFImageObj_GetImageMetadata(obj, page, &metadata));
+  EXPECT_EQ(92u, metadata.width);
+  EXPECT_EQ(68u, metadata.height);
+  EXPECT_NEAR(96.000000, metadata.horizontal_dpi, 0.001);
+  EXPECT_NEAR(96.000000, metadata.vertical_dpi, 0.001);
+  EXPECT_EQ(1u, metadata.bits_per_pixel);
+  EXPECT_EQ(FPDF_COLORSPACE_INDEXED, metadata.colorspace);
+
+  // Verify the metadata of an image with RGB colorspace.
+  obj = FPDFPage_GetObject(page, 37);
+  ASSERT_EQ(FPDF_PAGEOBJ_IMAGE, FPDFPageObj_GetType(obj));
+  ASSERT_TRUE(FPDFImageObj_GetImageMetadata(obj, page, &metadata));
+  EXPECT_EQ(126u, metadata.width);
+  EXPECT_EQ(106u, metadata.height);
+  EXPECT_NEAR(162.173752, metadata.horizontal_dpi, 0.001);
+  EXPECT_NEAR(162.555878, metadata.vertical_dpi, 0.001);
+  EXPECT_EQ(24u, metadata.bits_per_pixel);
+  EXPECT_EQ(FPDF_COLORSPACE_DEVICERGB, metadata.colorspace);
+
+  UnloadPage(page);
+}