Open FPDFDest_GetView API.

FPDFDest_GetView returns the view fit type and the parameters of the
view for a given destination.

This is useful to have more precise internal links and bookmarks that
are able to manipulate the viewport position and zoom level to focus
on the part of the PDF that it links to.

Bug: 55776, 535978, 748852
Change-Id: Ibf7df40a852030d75ec78cec7662380319569850
Reviewed-on: https://pdfium-review.googlesource.com/21790
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>

3 files changed, 84 insertions, 0 deletions

diff --git a/fpdfsdk/fpdfdoc.cpp b/fpdfsdk/fpdfdoc.cpp
index 4d2942fb31..51a1c61e77 100644
--- a/fpdfsdk/fpdfdoc.cpp
+++ b/fpdfsdk/fpdfdoc.cpp
@@ -210,6 +210,30 @@ FPDFDest_GetPageIndex(FPDF_DOCUMENT document, FPDF_DEST pDict) {
   return dest.GetPageIndex(pDoc);
 }
 
+FPDF_EXPORT unsigned long FPDF_CALLCONV
+FPDFDest_GetView(FPDF_DOCUMENT document,
+                 FPDF_DEST pDict,
+                 unsigned long* outNumParams,
+                 FS_FLOAT* outParams) {
+  if (!pDict) {
+    *outNumParams = 0;
+    return 0;
+  }
+
+  CPDF_Document* pDoc = CPDFDocumentFromFPDFDocument(document);
+  if (!pDoc) {
+    *outNumParams = 0;
+    return 0;
+  }
+
+  CPDF_Dest dest(static_cast<CPDF_Array*>(pDict));
+
+  *outNumParams = dest.GetNumParams();
+  for (unsigned long i = 0; i < *outNumParams; ++i)
+    outParams[i] = dest.GetParam(i);
+  return dest.GetZoomMode();
+}
+
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFDest_GetLocationInPage(FPDF_DEST pDict,
                            FPDF_BOOL* hasXVal,
diff --git a/fpdfsdk/fpdfdoc_embeddertest.cpp b/fpdfsdk/fpdfdoc_embeddertest.cpp
index c691a17a11..24414a1c33 100644
--- a/fpdfsdk/fpdfdoc_embeddertest.cpp
+++ b/fpdfsdk/fpdfdoc_embeddertest.cpp
@@ -42,6 +42,65 @@ TEST_F(FPDFDocEmbeddertest, DestGetPageIndex) {
   EXPECT_EQ(0U, FPDFDest_GetPageIndex(document(), dest));
 }
 
+TEST_F(FPDFDocEmbeddertest, DestGetView) {
+  EXPECT_TRUE(OpenDocument("named_dests.pdf"));
+
+  unsigned long numParams;
+  FS_FLOAT params[4];
+
+  numParams = 42;
+  std::fill_n(params, 4, 42.4242f);
+  EXPECT_EQ(static_cast<unsigned long>(PDFDEST_VIEW_UNKNOWN_MODE),
+            FPDFDest_GetView(document(), nullptr, &numParams, params));
+  EXPECT_EQ(0U, numParams);
+  EXPECT_FLOAT_EQ(42.4242f, params[0]);
+
+  numParams = 42;
+  std::fill_n(params, 4, 42.4242f);
+  FPDF_DEST dest = FPDF_GetNamedDestByName(document(), "First");
+  EXPECT_TRUE(dest);
+  EXPECT_EQ(static_cast<unsigned long>(PDFDEST_VIEW_XYZ),
+            FPDFDest_GetView(document(), dest, &numParams, params));
+  EXPECT_EQ(3U, numParams);
+  EXPECT_FLOAT_EQ(0, params[0]);
+  EXPECT_FLOAT_EQ(0, params[1]);
+  EXPECT_FLOAT_EQ(1, params[2]);
+  EXPECT_FLOAT_EQ(42.4242f, params[3]);
+
+  numParams = 42;
+  std::fill_n(params, 4, 42.4242f);
+  dest = FPDF_GetNamedDestByName(document(), "Next");
+  EXPECT_TRUE(dest);
+  EXPECT_EQ(static_cast<unsigned long>(PDFDEST_VIEW_FIT),
+            FPDFDest_GetView(document(), dest, &numParams, params));
+  EXPECT_EQ(0U, numParams);
+  EXPECT_FLOAT_EQ(42.4242f, params[0]);
+
+  numParams = 42;
+  std::fill_n(params, 4, 42.4242f);
+  dest = FPDF_GetNamedDestByName(document(), "FirstAlternate");
+  EXPECT_TRUE(dest);
+  EXPECT_EQ(static_cast<unsigned long>(PDFDEST_VIEW_XYZ),
+            FPDFDest_GetView(document(), dest, &numParams, params));
+  EXPECT_EQ(3U, numParams);
+  EXPECT_FLOAT_EQ(200, params[0]);
+  EXPECT_FLOAT_EQ(400, params[1]);
+  EXPECT_FLOAT_EQ(800, params[2]);
+  EXPECT_FLOAT_EQ(42.4242f, params[3]);
+
+  numParams = 42;
+  std::fill_n(params, 4, 42.4242f);
+  dest = FPDF_GetNamedDestByName(document(), "LastAlternate");
+  EXPECT_TRUE(dest);
+  EXPECT_EQ(static_cast<unsigned long>(PDFDEST_VIEW_XYZ),
+            FPDFDest_GetView(document(), dest, &numParams, params));
+  EXPECT_EQ(3U, numParams);
+  EXPECT_FLOAT_EQ(0, params[0]);
+  EXPECT_FLOAT_EQ(0, params[1]);
+  EXPECT_FLOAT_EQ(-200, params[2]);
+  EXPECT_FLOAT_EQ(42.4242f, params[3]);
+}
+
 TEST_F(FPDFDocEmbeddertest, DestGetLocationInPage) {
   EXPECT_TRUE(OpenDocument("named_dests.pdf"));
 
diff --git a/fpdfsdk/fpdfview_c_api_test.c b/fpdfsdk/fpdfview_c_api_test.c
index de4fa1c564..199c383ae5 100644
--- a/fpdfsdk/fpdfview_c_api_test.c
+++ b/fpdfsdk/fpdfview_c_api_test.c
@@ -107,6 +107,7 @@ int CheckPDFiumCApi() {
     CHK(FPDFAction_GetURIPath);
     CHK(FPDFDest_GetPageIndex);
     CHK(FPDFDest_GetLocationInPage);
+    CHK(FPDFDest_GetView);
     CHK(FPDFLink_GetLinkAtPoint);
     CHK(FPDFLink_GetLinkZOrderAtPoint);
     CHK(FPDFLink_GetDest);