Add return value to FPDF_DeviceToPage().

Do the same for FPDF_PageToDevice(). Clean up the internal
implementation as well.

Change-Id: Ia207bfa779d144cb9f0310e768750ab10e603b8f
Reviewed-on: https://pdfium-review.googlesource.com/17370
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

6 files changed, 99 insertions, 106 deletions

diff --git a/core/fpdfapi/page/cpdf_page.cpp b/core/fpdfapi/page/cpdf_page.cpp
index 06043ead35..259e8ce0fb 100644
--- a/core/fpdfapi/page/cpdf_page.cpp
+++ b/core/fpdfapi/page/cpdf_page.cpp
@@ -118,30 +118,21 @@ CFX_FloatRect CPDF_Page::GetBox(const ByteString& name) const {
   return box;
 }
 
-void CPDF_Page::DeviceToPage(const FX_RECT& rect,
-                             int rotate,
-                             const CFX_PointF& device_point,
-                             double* page_x,
-                             double* page_y) const {
+Optional<CFX_PointF> CPDF_Page::DeviceToPage(
+    const FX_RECT& rect,
+    int rotate,
+    const CFX_PointF& device_point) const {
   CFX_Matrix page2device = GetDisplayMatrix(rect, rotate);
-  CFX_PointF pos = page2device.GetInverse().Transform(device_point);
-
-  *page_x = pos.x;
-  *page_y = pos.y;
+  return page2device.GetInverse().Transform(device_point);
 }
 
-void CPDF_Page::PageToDevice(const FX_RECT& rect,
-                             int rotate,
-                             double page_x,
-                             double page_y,
-                             int* device_x,
-                             int* device_y) const {
+Optional<CFX_PointF> CPDF_Page::PageToDevice(const FX_RECT& rect,
+                                             int rotate,
+                                             double page_x,
+                                             double page_y) const {
   CFX_Matrix page2device = GetDisplayMatrix(rect, rotate);
-  CFX_PointF pos = page2device.Transform(
+  return page2device.Transform(
       CFX_PointF(static_cast<float>(page_x), static_cast<float>(page_y)));
-
-  *device_x = FXSYS_round(pos.x);
-  *device_y = FXSYS_round(pos.y);
 }
 
 CFX_Matrix CPDF_Page::GetDisplayMatrix(const FX_RECT& rect, int iRotate) const {
diff --git a/core/fpdfapi/page/cpdf_page.h b/core/fpdfapi/page/cpdf_page.h
index d199ea41db..34c9ef45a8 100644
--- a/core/fpdfapi/page/cpdf_page.h
+++ b/core/fpdfapi/page/cpdf_page.h
@@ -12,6 +12,7 @@
 #include "core/fpdfapi/page/cpdf_pageobjectholder.h"
 #include "core/fxcrt/fx_coordinates.h"
 #include "core/fxcrt/fx_system.h"
+#include "third_party/base/optional.h"
 
 class CPDF_Dictionary;
 class CPDF_Document;
@@ -33,17 +34,13 @@ class CPDF_Page : public CPDF_PageObjectHolder {
 
   void ParseContent();
 
-  void DeviceToPage(const FX_RECT& rect,
-                    int rotate,
-                    const CFX_PointF& device_point,
-                    double* page_x,
-                    double* page_y) const;
-  void PageToDevice(const FX_RECT& rect,
-                    int rotate,
-                    double page_x,
-                    double page_y,
-                    int* device_x,
-                    int* device_y) const;
+  Optional<CFX_PointF> DeviceToPage(const FX_RECT& rect,
+                                    int rotate,
+                                    const CFX_PointF& device_point) const;
+  Optional<CFX_PointF> PageToDevice(const FX_RECT& rect,
+                                    int rotate,
+                                    double page_x,
+                                    double page_y) const;
 
   CFX_Matrix GetDisplayMatrix(const FX_RECT& rect, int iRotate) const;
 
diff --git a/fpdfsdk/fpdf_view.cpp b/fpdfsdk/fpdf_view.cpp
index f39d80cab0..f2fa43f369 100644
--- a/fpdfsdk/fpdf_view.cpp
+++ b/fpdfsdk/fpdf_view.cpp
@@ -731,41 +731,53 @@ FPDF_EXPORT unsigned long FPDF_CALLCONV FPDF_GetLastError() {
   return GetLastError();
 }
 
-FPDF_EXPORT void FPDF_CALLCONV FPDF_DeviceToPage(FPDF_PAGE page,
-                                                 int start_x,
-                                                 int start_y,
-                                                 int size_x,
-                                                 int size_y,
-                                                 int rotate,
-                                                 int device_x,
-                                                 int device_y,
-                                                 double* page_x,
-                                                 double* page_y) {
+FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDF_DeviceToPage(FPDF_PAGE page,
+                                                      int start_x,
+                                                      int start_y,
+                                                      int size_x,
+                                                      int size_y,
+                                                      int rotate,
+                                                      int device_x,
+                                                      int device_y,
+                                                      double* page_x,
+                                                      double* page_y) {
   if (!page || !page_x || !page_y)
-    return;
+    return false;
 
   UnderlyingPageType* pPage = UnderlyingFromFPDFPage(page);
   const FX_RECT rect(start_x, start_y, start_x + size_x, start_y + size_y);
-  pPage->DeviceToPage(rect, rotate, CFX_PointF(device_x, device_y), page_x,
-                      page_y);
+  Optional<CFX_PointF> pos =
+      pPage->DeviceToPage(rect, rotate, CFX_PointF(device_x, device_y));
+  if (!pos)
+    return false;
+
+  *page_x = pos->x;
+  *page_y = pos->y;
+  return true;
 }
 
-FPDF_EXPORT void FPDF_CALLCONV FPDF_PageToDevice(FPDF_PAGE page,
-                                                 int start_x,
-                                                 int start_y,
-                                                 int size_x,
-                                                 int size_y,
-                                                 int rotate,
-                                                 double page_x,
-                                                 double page_y,
-                                                 int* device_x,
-                                                 int* device_y) {
+FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDF_PageToDevice(FPDF_PAGE page,
+                                                      int start_x,
+                                                      int start_y,
+                                                      int size_x,
+                                                      int size_y,
+                                                      int rotate,
+                                                      double page_x,
+                                                      double page_y,
+                                                      int* device_x,
+                                                      int* device_y) {
   if (!page || !device_x || !device_y)
-    return;
+    return false;
 
   UnderlyingPageType* pPage = UnderlyingFromFPDFPage(page);
   const FX_RECT rect(start_x, start_y, start_x + size_x, start_y + size_y);
-  pPage->PageToDevice(rect, rotate, page_x, page_y, device_x, device_y);
+  Optional<CFX_PointF> pos = pPage->PageToDevice(rect, rotate, page_x, page_y);
+  if (!pos)
+    return false;
+
+  *device_x = FXSYS_round(pos->x);
+  *device_y = FXSYS_round(pos->y);
+  return true;
 }
 
 FPDF_EXPORT FPDF_BITMAP FPDF_CALLCONV FPDFBitmap_Create(int width,
diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_page.cpp b/fpdfsdk/fpdfxfa/cpdfxfa_page.cpp
index d4a6d95574..8fea85d72b 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_page.cpp
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_page.cpp
@@ -126,34 +126,28 @@ float CPDFXFA_Page::GetPageHeight() const {
   return 0.0f;
 }
 
-void CPDFXFA_Page::DeviceToPage(const FX_RECT& rect,
-                                int rotate,
-                                const CFX_PointF& device_point,
-                                double* page_x,
-                                double* page_y) const {
+Optional<CFX_PointF> CPDFXFA_Page::DeviceToPage(
+    const FX_RECT& rect,
+    int rotate,
+    const CFX_PointF& device_point) const {
   if (!m_pPDFPage && !m_pXFAPageView)
-    return;
+    return {};
 
   CFX_PointF pos =
       GetDisplayMatrix(rect, rotate).GetInverse().Transform(device_point);
-  *page_x = pos.x;
-  *page_y = pos.y;
+  return pos;
 }
 
-void CPDFXFA_Page::PageToDevice(const FX_RECT& rect,
-                                int rotate,
-                                double page_x,
-                                double page_y,
-                                int* device_x,
-                                int* device_y) const {
+Optional<CFX_PointF> CPDFXFA_Page::PageToDevice(const FX_RECT& rect,
+                                                int rotate,
+                                                double page_x,
+                                                double page_y) const {
   if (!m_pPDFPage && !m_pXFAPageView)
-    return;
+    return {};
 
   CFX_Matrix page2device = GetDisplayMatrix(rect, rotate);
-  CFX_PointF pos = page2device.Transform(
+  return page2device.Transform(
       CFX_PointF(static_cast<float>(page_x), static_cast<float>(page_y)));
-  *device_x = FXSYS_round(pos.x);
-  *device_y = FXSYS_round(pos.y);
 }
 
 CFX_Matrix CPDFXFA_Page::GetDisplayMatrix(const FX_RECT& rect,
diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_page.h b/fpdfsdk/fpdfxfa/cpdfxfa_page.h
index aef1b0b539..131e811b66 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_page.h
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_page.h
@@ -13,6 +13,7 @@
 #include "core/fxcrt/fx_system.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/unowned_ptr.h"
+#include "third_party/base/optional.h"
 
 class CPDFXFA_Context;
 class CPDF_Dictionary;
@@ -38,17 +39,13 @@ class CPDFXFA_Page : public Retainable {
   float GetPageWidth() const;
   float GetPageHeight() const;
 
-  void DeviceToPage(const FX_RECT& rect,
-                    int rotate,
-                    const CFX_PointF& device_point,
-                    double* page_x,
-                    double* page_y) const;
-  void PageToDevice(const FX_RECT& rect,
-                    int rotate,
-                    double page_x,
-                    double page_y,
-                    int* device_x,
-                    int* device_y) const;
+  Optional<CFX_PointF> DeviceToPage(const FX_RECT& rect,
+                                    int rotate,
+                                    const CFX_PointF& device_point) const;
+  Optional<CFX_PointF> PageToDevice(const FX_RECT& rect,
+                                    int rotate,
+                                    double page_x,
+                                    double page_y) const;
 
   CFX_Matrix GetDisplayMatrix(const FX_RECT& rect, int iRotate) const;
 
diff --git a/public/fpdfview.h b/public/fpdfview.h
index 62b7b88410..2c93e962f3 100644
--- a/public/fpdfview.h
+++ b/public/fpdfview.h
@@ -736,7 +736,8 @@ FPDF_EXPORT void FPDF_CALLCONV FPDF_CloseDocument(FPDF_DOCUMENT document);
 //          page_y      -   A pointer to a double receiving the converted Y
 //                          value in page coordinates.
 // Return value:
-//          None.
+//          Returns true if the conversion succeeds, and |page_x| and |page_y|
+//          successfully receives the converted coordinates.
 // Comments:
 //          The page coordinate system has its origin at the left-bottom corner
 //          of the page, with the X-axis on the bottom going to the right, and
@@ -754,16 +755,16 @@ FPDF_EXPORT void FPDF_CALLCONV FPDF_CloseDocument(FPDF_DOCUMENT document);
 //          You must make sure the start_x, start_y, size_x, size_y
 //          and rotate parameters have exactly same values as you used in
 //          the FPDF_RenderPage() function call.
-FPDF_EXPORT void FPDF_CALLCONV FPDF_DeviceToPage(FPDF_PAGE page,
-                                                 int start_x,
-                                                 int start_y,
-                                                 int size_x,
-                                                 int size_y,
-                                                 int rotate,
-                                                 int device_x,
-                                                 int device_y,
-                                                 double* page_x,
-                                                 double* page_y);
+FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDF_DeviceToPage(FPDF_PAGE page,
+                                                      int start_x,
+                                                      int start_y,
+                                                      int size_x,
+                                                      int size_y,
+                                                      int rotate,
+                                                      int device_x,
+                                                      int device_y,
+                                                      double* page_x,
+                                                      double* page_y);
 
 // Function: FPDF_PageToDevice
 //          Convert the page coordinates of a point to screen coordinates.
@@ -787,19 +788,20 @@ FPDF_EXPORT void FPDF_CALLCONV FPDF_DeviceToPage(FPDF_PAGE page,
 //          device_y    -   A pointer to an integer receiving the result Y
 //                          value in device coordinates.
 // Return value:
-//          None.
+//          Returns true if the conversion succeeds, and |device_x| and
+//          |device_y| successfully receives the converted coordinates.
 // Comments:
 //          See comments for FPDF_DeviceToPage().
-FPDF_EXPORT void FPDF_CALLCONV FPDF_PageToDevice(FPDF_PAGE page,
-                                                 int start_x,
-                                                 int start_y,
-                                                 int size_x,
-                                                 int size_y,
-                                                 int rotate,
-                                                 double page_x,
-                                                 double page_y,
-                                                 int* device_x,
-                                                 int* device_y);
+FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDF_PageToDevice(FPDF_PAGE page,
+                                                      int start_x,
+                                                      int start_y,
+                                                      int size_x,
+                                                      int size_y,
+                                                      int rotate,
+                                                      double page_x,
+                                                      double page_y,
+                                                      int* device_x,
+                                                      int* device_y);
 
 // Function: FPDFBitmap_Create
 //          Create a device independent bitmap (FXDIB).