fpdf_progressive.cpp

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// Copyright 2014 The PDFium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
#include "public/fpdf_progressive.h"
 
#include <memory>
#include <utility>
 
#include "core/fpdfapi/page/cpdf_page.h"
#include "core/fpdfapi/render/cpdf_pagerendercontext.h"
#include "core/fpdfapi/render/cpdf_progressiverenderer.h"
#include "core/fxge/cfx_defaultrenderdevice.h"
#include "core/fxge/dib/cfx_dibitmap.h"
#include "fpdfsdk/cpdfsdk_helpers.h"
#include "fpdfsdk/cpdfsdk_pauseadapter.h"
#include "fpdfsdk/cpdfsdk_renderpage.h"
#include "public/fpdfview.h"
 
// These checks are here because core/ and public/ cannot depend on each other.
static_assert(CPDF_ProgressiveRenderer::kReady == FPDF_RENDER_READY,
              "CPDF_ProgressiveRenderer::kReady value mismatch");
static_assert(CPDF_ProgressiveRenderer::kToBeContinued ==
                  FPDF_RENDER_TOBECONTINUED,
              "CPDF_ProgressiveRenderer::kToBeContinued value mismatch");
static_assert(CPDF_ProgressiveRenderer::kDone == FPDF_RENDER_DONE,
              "CPDF_ProgressiveRenderer::kDone value mismatch");
static_assert(CPDF_ProgressiveRenderer::kFailed == FPDF_RENDER_FAILED,
              "CPDF_ProgressiveRenderer::kFailed value mismatch");
 
namespace {
 
int ToFPDFStatus(CPDF_ProgressiveRenderer::Status status) {
  return static_cast<int>(status);
}
 
}  // namespace
 
FPDF_EXPORT int FPDF_CALLCONV
FPDF_RenderPageBitmapWithColorScheme_Start(FPDF_BITMAP bitmap,
                                           FPDF_PAGE page,
                                           int start_x,
                                           int start_y,
                                           int size_x,
                                           int size_y,
                                           int rotate,
                                           int flags,
                                           const FPDF_COLORSCHEME* color_scheme,
                                           IFSDK_PAUSE* pause) {
  if (!pause || pause->version != 1) {
    return FPDF_RENDER_FAILED;
  }
 
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  if (!pPage) {
    return FPDF_RENDER_FAILED;
  }
 
  RetainPtr<CFX_DIBitmap> pBitmap(CFXDIBitmapFromFPDFBitmap(bitmap));
  if (!pBitmap) {
    return FPDF_RENDER_FAILED;
  }
  CHECK(!pBitmap->IsPremultiplied());
 
  auto owned_context = std::make_unique<CPDF_PageRenderContext>();
  CPDF_PageRenderContext* context = owned_context.get();
  pPage->SetRenderContext(std::move(owned_context));
 
#if defined(PDF_USE_SKIA)
  if (CFX_DefaultRenderDevice::UseSkiaRenderer()) {
    pBitmap->PreMultiply();
  }
#endif
 
  auto device = std::make_unique<CFX_DefaultRenderDevice>();
  device->AttachWithRgbByteOrder(pBitmap, !!(flags & FPDF_REVERSE_BYTE_ORDER));
  context->m_pDevice = std::move(device);
 
  CPDFSDK_PauseAdapter pause_adapter(pause);
  CPDFSDK_RenderPageWithContext(context, pPage, start_x, start_y, size_x,
                                size_y, rotate, flags, color_scheme,
                                /*need_to_restore=*/false, &pause_adapter);
 
  if (!context->m_pRenderer) {
#if defined(PDF_USE_SKIA)
    if (CFX_DefaultRenderDevice::UseSkiaRenderer()) {
      pBitmap->UnPreMultiply();
    }
#endif  // defined(PDF_USE_SKIA)
 
    return FPDF_RENDER_FAILED;
  }
 
  int status = ToFPDFStatus(context->m_pRenderer->GetStatus());
  if (status == FPDF_RENDER_TOBECONTINUED) {
    // Note that `pBitmap` is still pre-multiplied here, as the caller is
    // expected to pass it to FPDF_RenderPage_Continue(). Then
    // FPDF_RenderPage_Continue() can continue rendering into it without doing
    // another round of (un)pre-multiplication. FPDF_RenderPage_Continue() will
    // call UnPreMultiply() when done.
    //
    // Normally, PDFium would not return a pre-multiplied bitmap to the caller,
    // but in this case, the bitmap is in an indeterminate state while it is
    // being progressively rendered. So many an exception here, as it can
    // greatly improve performance.
    return FPDF_RENDER_TOBECONTINUED;
  }
 
#if defined(PDF_USE_SKIA)
  if (CFX_DefaultRenderDevice::UseSkiaRenderer()) {
    pBitmap->UnPreMultiply();
  }
#endif  // defined(PDF_USE_SKIA)
  return status;
}
 
FPDF_EXPORT int FPDF_CALLCONV FPDF_RenderPageBitmap_Start(FPDF_BITMAP bitmap,
                                                          FPDF_PAGE page,
                                                          int start_x,
                                                          int start_y,
                                                          int size_x,
                                                          int size_y,
                                                          int rotate,
                                                          int flags,
                                                          IFSDK_PAUSE* pause) {
  return FPDF_RenderPageBitmapWithColorScheme_Start(
      bitmap, page, start_x, start_y, size_x, size_y, rotate, flags,
      /*color_scheme=*/nullptr, pause);
}
 
FPDF_EXPORT int FPDF_CALLCONV FPDF_RenderPage_Continue(FPDF_PAGE page,
                                                       IFSDK_PAUSE* pause) {
  if (!pause || pause->version != 1)
    return FPDF_RENDER_FAILED;
 
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  if (!pPage)
    return FPDF_RENDER_FAILED;
 
  auto* pContext =
      static_cast<CPDF_PageRenderContext*>(pPage->GetRenderContext());
  if (!pContext || !pContext->m_pRenderer)
    return FPDF_RENDER_FAILED;
 
  CPDFSDK_PauseAdapter pause_adapter(pause);
  pContext->m_pRenderer->Continue(&pause_adapter);
 
  int status = ToFPDFStatus(pContext->m_pRenderer->GetStatus());
  if (status == FPDF_RENDER_TOBECONTINUED) {
    return FPDF_RENDER_TOBECONTINUED;
  }
 
#if defined(PDF_USE_SKIA)
  if (CFX_DefaultRenderDevice::UseSkiaRenderer()) {
    pContext->m_pDevice->GetBitmap()->UnPreMultiply();
  }
#endif  // defined(PDF_USE_SKIA)
  return status;
}
 
FPDF_EXPORT void FPDF_CALLCONV FPDF_RenderPage_Close(FPDF_PAGE page) {
  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
  if (pPage)
    pPage->ClearRenderContext();
}