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 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. 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. 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 { 125 126 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