1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "ui/gfx/gdi_util.h"
6
7#include "base/logging.h"
8#include "base/memory/scoped_ptr.h"
9
10namespace gfx {
11
12void CreateBitmapHeader(int width, int height, BITMAPINFOHEADER* hdr) {
13  CreateBitmapHeaderWithColorDepth(width, height, 32, hdr);
14}
15
16void CreateBitmapHeaderWithColorDepth(int width, int height, int color_depth,
17                                      BITMAPINFOHEADER* hdr) {
18  // These values are shared with gfx::PlatformDevice
19  hdr->biSize = sizeof(BITMAPINFOHEADER);
20  hdr->biWidth = width;
21  hdr->biHeight = -height;  // minus means top-down bitmap
22  hdr->biPlanes = 1;
23  hdr->biBitCount = color_depth;
24  hdr->biCompression = BI_RGB;  // no compression
25  hdr->biSizeImage = 0;
26  hdr->biXPelsPerMeter = 1;
27  hdr->biYPelsPerMeter = 1;
28  hdr->biClrUsed = 0;
29  hdr->biClrImportant = 0;
30}
31
32void CreateBitmapV4Header(int width, int height, BITMAPV4HEADER* hdr) {
33  // Because bmp v4 header is just an extension, we just create a v3 header and
34  // copy the bits over to the v4 header.
35  BITMAPINFOHEADER header_v3;
36  CreateBitmapHeader(width, height, &header_v3);
37  memset(hdr, 0, sizeof(BITMAPV4HEADER));
38  memcpy(hdr, &header_v3, sizeof(BITMAPINFOHEADER));
39
40  // Correct the size of the header and fill in the mask values.
41  hdr->bV4Size = sizeof(BITMAPV4HEADER);
42  hdr->bV4RedMask   = 0x00ff0000;
43  hdr->bV4GreenMask = 0x0000ff00;
44  hdr->bV4BlueMask  = 0x000000ff;
45  hdr->bV4AlphaMask = 0xff000000;
46}
47
48// Creates a monochrome bitmap header.
49void CreateMonochromeBitmapHeader(int width,
50                                  int height,
51                                  BITMAPINFOHEADER* hdr) {
52  hdr->biSize = sizeof(BITMAPINFOHEADER);
53  hdr->biWidth = width;
54  hdr->biHeight = -height;
55  hdr->biPlanes = 1;
56  hdr->biBitCount = 1;
57  hdr->biCompression = BI_RGB;
58  hdr->biSizeImage = 0;
59  hdr->biXPelsPerMeter = 1;
60  hdr->biYPelsPerMeter = 1;
61  hdr->biClrUsed = 0;
62  hdr->biClrImportant = 0;
63}
64
65void SubtractRectanglesFromRegion(HRGN hrgn,
66                                  const std::vector<gfx::Rect>& cutouts) {
67  if (cutouts.size()) {
68    HRGN cutout = ::CreateRectRgn(0, 0, 0, 0);
69    for (size_t i = 0; i < cutouts.size(); i++) {
70      ::SetRectRgn(cutout,
71                   cutouts[i].x(),
72                   cutouts[i].y(),
73                   cutouts[i].right(),
74                   cutouts[i].bottom());
75      ::CombineRgn(hrgn, hrgn, cutout, RGN_DIFF);
76    }
77    ::DeleteObject(cutout);
78  }
79}
80
81HRGN ConvertPathToHRGN(const gfx::Path& path) {
82#if defined(USE_AURA)
83  int point_count = path.getPoints(NULL, 0);
84  scoped_ptr<SkPoint[]> points(new SkPoint[point_count]);
85  path.getPoints(points.get(), point_count);
86  scoped_ptr<POINT[]> windows_points(new POINT[point_count]);
87  for (int i = 0; i < point_count; ++i) {
88    windows_points[i].x = SkScalarRoundToInt(points[i].fX);
89    windows_points[i].y = SkScalarRoundToInt(points[i].fY);
90  }
91
92  return ::CreatePolygonRgn(windows_points.get(), point_count, ALTERNATE);
93#elif defined(OS_WIN)
94  return path.CreateNativeRegion();
95#endif
96}
97
98
99double CalculatePageScale(HDC dc, int page_width, int page_height) {
100  int dc_width = GetDeviceCaps(dc, HORZRES);
101  int dc_height = GetDeviceCaps(dc, VERTRES);
102
103  // If page fits DC - no scaling needed.
104  if (dc_width >= page_width && dc_height >= page_height)
105    return 1.0;
106
107  double x_factor =
108      static_cast<double>(dc_width) / static_cast<double>(page_width);
109  double y_factor =
110      static_cast<double>(dc_height) / static_cast<double>(page_height);
111  return std::min(x_factor, y_factor);
112}
113
114// Apply scaling to the DC.
115bool ScaleDC(HDC dc, double scale_factor) {
116  SetGraphicsMode(dc, GM_ADVANCED);
117  XFORM xform = {0};
118  xform.eM11 = xform.eM22 = scale_factor;
119  return !!ModifyWorldTransform(dc, &xform, MWT_LEFTMULTIPLY);
120}
121
122void StretchDIBits(HDC hdc, int dest_x, int dest_y, int dest_w, int dest_h,
123                   int src_x, int src_y, int src_w, int src_h, void* pixels,
124                   const BITMAPINFO* bitmap_info) {
125  // When blitting a rectangle that touches the bottom, left corner of the
126  // bitmap, StretchDIBits looks at it top-down!  For more details, see
127  // http://wiki.allegro.cc/index.php?title=StretchDIBits.
128  int rv;
129  int bitmap_h = -bitmap_info->bmiHeader.biHeight;
130  int bottom_up_src_y = bitmap_h - src_y - src_h;
131  if (bottom_up_src_y == 0 && src_x == 0 && src_h != bitmap_h) {
132    rv = ::StretchDIBits(hdc,
133                         dest_x, dest_h + dest_y - 1, dest_w, -dest_h,
134                         src_x, bitmap_h - src_y + 1, src_w, -src_h,
135                         pixels, bitmap_info, DIB_RGB_COLORS, SRCCOPY);
136  } else {
137    rv = ::StretchDIBits(hdc,
138                         dest_x, dest_y, dest_w, dest_h,
139                         src_x, bottom_up_src_y, src_w, src_h,
140                         pixels, bitmap_info, DIB_RGB_COLORS, SRCCOPY);
141  }
142  DCHECK(rv != GDI_ERROR);
143}
144
145}  // namespace gfx
146