1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
/******************************************************************************
*
* Project: GDAL Core
* Purpose: Implementation of GDALRescaledAlphaBand, a class implementing
* a band mask based from a non-GDT_Byte alpha band
* Author: Even Rouault, <even dot rouault at spatialys dot com>
*
******************************************************************************
* Copyright (c) 2014, Even Rouault <even dot rouault at spatialys dot com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
****************************************************************************/
#include "cpl_port.h"
#include "gdal_priv.h"
#include <cstddef>
#include "cpl_error.h"
#include "cpl_vsi.h"
#include "gdal.h"
//! @cond Doxygen_Suppress
/************************************************************************/
/* GDALRescaledAlphaBand() */
/************************************************************************/
GDALRescaledAlphaBand::GDALRescaledAlphaBand(GDALRasterBand *poParentIn)
: poParent(poParentIn), pTemp(nullptr)
{
CPLAssert(poParent->GetRasterDataType() == GDT_UInt16);
// Defined in GDALRasterBand.
poDS = nullptr;
nBand = 0;
nRasterXSize = poParent->GetXSize();
nRasterYSize = poParent->GetYSize();
eDataType = GDT_Byte;
poParent->GetBlockSize(&nBlockXSize, &nBlockYSize);
}
/************************************************************************/
/* ~GDALRescaledAlphaBand() */
/************************************************************************/
GDALRescaledAlphaBand::~GDALRescaledAlphaBand()
{
VSIFree(pTemp);
}
/************************************************************************/
/* IReadBlock() */
/************************************************************************/
CPLErr GDALRescaledAlphaBand::IReadBlock(int nXBlockOff, int nYBlockOff,
void *pImage)
{
int nXSizeRequest = nBlockXSize;
if (nXBlockOff * nBlockXSize + nBlockXSize > nRasterXSize)
nXSizeRequest = nRasterXSize - nXBlockOff * nBlockXSize;
int nYSizeRequest = nBlockYSize;
if (nYBlockOff * nBlockYSize + nBlockYSize > nRasterYSize)
nYSizeRequest = nRasterYSize - nYBlockOff * nBlockYSize;
GDALRasterIOExtraArg sExtraArg;
INIT_RASTERIO_EXTRA_ARG(sExtraArg);
return IRasterIO(GF_Read, nXBlockOff * nBlockXSize,
nYBlockOff * nBlockYSize, nXSizeRequest, nYSizeRequest,
pImage, nXSizeRequest, nYSizeRequest, GDT_Byte, 1,
nBlockXSize, &sExtraArg);
}
/************************************************************************/
/* IRasterIO() */
/************************************************************************/
CPLErr GDALRescaledAlphaBand::IRasterIO(
GDALRWFlag eRWFlag, int nXOff, int nYOff, int nXSize, int nYSize,
void *pData, int nBufXSize, int nBufYSize, GDALDataType eBufType,
GSpacing nPixelSpace, GSpacing nLineSpace, GDALRasterIOExtraArg *psExtraArg)
{
// Optimization in common use case.
// This avoids triggering the block cache on this band, which helps
// reducing the global block cache consumption.
if (eRWFlag == GF_Read && eBufType == GDT_Byte && nXSize == nBufXSize &&
nYSize == nBufYSize && nPixelSpace == 1)
{
if (pTemp == nullptr)
{
pTemp = VSI_MALLOC2_VERBOSE(sizeof(GUInt16), nRasterXSize);
if (pTemp == nullptr)
{
return CE_Failure;
}
}
for (int j = 0; j < nBufYSize; j++)
{
const CPLErr eErr =
poParent->RasterIO(GF_Read, nXOff, nYOff + j, nXSize, 1, pTemp,
nBufXSize, 1, GDT_UInt16, 0, 0, nullptr);
if (eErr != CE_None)
return eErr;
GByte *pabyImage = static_cast<GByte *>(pData) + j * nLineSpace;
GUInt16 *pSrc = static_cast<GUInt16 *>(pTemp);
for (int i = 0; i < nBufXSize; i++)
{
// In case the dynamics was actually 0-255 and not 0-65535 as
// expected, we want to make sure non-zero alpha will still
// be non-zero.
if (pSrc[i] > 0 && pSrc[i] < 257)
pabyImage[i] = 1;
else
pabyImage[i] = static_cast<GByte>((pSrc[i] * 255) / 65535);
}
}
return CE_None;
}
return GDALRasterBand::IRasterIO(eRWFlag, nXOff, nYOff, nXSize, nYSize,
pData, nBufXSize, nBufYSize, eBufType,
nPixelSpace, nLineSpace, psExtraArg);
}
//! @endcond
|
