1 // Copyright 2014 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/views/corewm/cursor_height_provider_win.h"
6
7 #include <windows.h>
8 #include <algorithm>
9 #include <map>
10
11 #include "base/basictypes.h"
12 #include "base/memory/scoped_ptr.h"
13 #include "base/win/scoped_hdc.h"
14
15 namespace {
16 typedef scoped_ptr<uint32_t> PixelData;
17 typedef std::map<HCURSOR, int> HeightStorage;
18
19 const uint32_t kBitsPeruint32 = sizeof(uint32_t) * 8;
20 // All bits are 1 for transparent portion of monochromatic mask.
21 const uint32_t kTransparentMask = 0xffffffff;
22 // This is height of default pointer arrow in Windows 7.
23 const int kDefaultHeight = 20;
24 // Masks are monochromatic.
25 const size_t kNumberOfColors = 2;
26 const size_t KHeaderAndPalette =
27 sizeof(BITMAPINFOHEADER) + kNumberOfColors * sizeof(RGBQUAD);
28
29 static HeightStorage* cached_heights = NULL;
30
31 // Extracts the pixel data of provided bitmap
GetBitmapData(HBITMAP handle,const BITMAPINFO & info,HDC hdc)32 PixelData GetBitmapData(HBITMAP handle, const BITMAPINFO& info, HDC hdc) {
33 PixelData data;
34 // Masks are monochromatic.
35 DCHECK_EQ(info.bmiHeader.biBitCount, 1);
36 if (info.bmiHeader.biBitCount != 1)
37 return data.Pass();
38
39 // When getting pixel data palette is appended to memory pointed by
40 // BITMAPINFO passed so allocate additional memory to store additional data.
41 scoped_ptr<BITMAPINFO> header(
42 reinterpret_cast<BITMAPINFO*>(new char[KHeaderAndPalette]));
43 memcpy(header.get(), &(info.bmiHeader), sizeof(info.bmiHeader));
44
45 data.reset(new uint32_t[info.bmiHeader.biSizeImage / sizeof(uint32_t)]);
46
47 int result = GetDIBits(hdc,
48 handle,
49 0,
50 info.bmiHeader.biHeight,
51 data.get(),
52 header.get(),
53 DIB_RGB_COLORS);
54
55 if (result == 0)
56 data.reset();
57
58 return data.Pass();
59 }
60
61 // Checks if the specifed row is transparent in provided bitmap.
IsRowTransparent(const PixelData & data,const uint32_t row_size,const uint32_t last_byte_mask,const uint32_t y)62 bool IsRowTransparent(const PixelData& data,
63 const uint32_t row_size,
64 const uint32_t last_byte_mask,
65 const uint32_t y) {
66 // Set the padding bits to 1 to make mask matching easier.
67 *(data.get() + (y + 1) * row_size - 1) |= last_byte_mask;
68 for (uint32_t i = y * row_size; i < (y + 1) * row_size; ++i) {
69 if (*(data.get() + i) != kTransparentMask)
70 return false;
71 }
72 return true;
73 }
74
75 // Gets the vertical offset between specified cursor's hotpoint and it's bottom.
76 //
77 // Gets the cursor image data and extract cursor's visible height.
78 // Based on that get's what should be the vertical offset between cursor's
79 // hot point and the tooltip.
CalculateCursorHeight(HCURSOR cursor_handle)80 int CalculateCursorHeight(HCURSOR cursor_handle) {
81 base::win::ScopedGetDC hdc(NULL);
82
83 ICONINFO icon = {0};
84 GetIconInfo(cursor_handle, &icon);
85
86 BITMAPINFO bitmap_info = {0};
87 bitmap_info.bmiHeader.biSize = sizeof(bitmap_info.bmiHeader);
88 if (GetDIBits(hdc, icon.hbmMask, 0, 0, NULL, &bitmap_info, DIB_RGB_COLORS) ==
89 0)
90 return kDefaultHeight;
91
92 // Rows are padded to full DWORDs. OR with this mask will set them to 1
93 // to simplify matching with |transparent_mask|.
94 uint32_t last_byte_mask = ~0;
95 const unsigned char bits_to_shift = sizeof(last_byte_mask) * 8 -
96 (bitmap_info.bmiHeader.biWidth % kBitsPeruint32);
97 if (bits_to_shift != kBitsPeruint32)
98 last_byte_mask = (last_byte_mask << bits_to_shift);
99 else
100 last_byte_mask = 0;
101
102 const uint32_t row_size =
103 (bitmap_info.bmiHeader.biWidth + kBitsPeruint32 - 1) / kBitsPeruint32;
104 PixelData data(GetBitmapData(icon.hbmMask, bitmap_info, hdc));
105 if (data == NULL)
106 return kDefaultHeight;
107
108 const int cursor_height = GetSystemMetrics(SM_CYCURSOR);
109 // Crash data seems to indicate cursor_height may be bigger than the bitmap.
110 int i = std::max(0, static_cast<int>(bitmap_info.bmiHeader.biHeight) -
111 cursor_height);
112 for (; i < bitmap_info.bmiHeader.biHeight; ++i) {
113 if (!IsRowTransparent(data, row_size, last_byte_mask, i)) {
114 i--;
115 break;
116 }
117 }
118 return bitmap_info.bmiHeader.biHeight - i - icon.yHotspot;
119 }
120
121 } // namespace
122
123 namespace views {
124 namespace corewm {
125
GetCurrentCursorVisibleHeight()126 int GetCurrentCursorVisibleHeight() {
127 CURSORINFO cursor = {0};
128 cursor.cbSize = sizeof(cursor);
129 GetCursorInfo(&cursor);
130
131 if (cached_heights == NULL)
132 cached_heights = new HeightStorage;
133
134 HeightStorage::const_iterator cached_height =
135 cached_heights->find(cursor.hCursor);
136 if (cached_height != cached_heights->end())
137 return cached_height->second;
138
139 const int height = CalculateCursorHeight(cursor.hCursor);
140 (*cached_heights)[cursor.hCursor] = height;
141
142 return height;
143 }
144
145 } // namespace corewm
146 } // namespace views
147