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imageresize.d
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imageresize.d
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/++
Image resizing support for [arsd.color.MemoryImage]. Handles up and down scaling.
See [imageResize] for the main function, all others are lower level if you need
more control.
Note that this focuses more on quality than speed. You can tweak the `filterScale`
argument to speed things up at the expense of quality though (lower number = faster).
I've found:
---
auto size = calculateSizeKeepingAspectRatio(i.width, i.height, maxWidth, maxHeight);
if(size.width != i.width || size.height != i.height) {
i = imageResize(i, size.width, size.height, null, 1.0, 0.6);
}
---
Gives decent results balancing quality and speed. Compiling with ldc or gdc can also
speed up your program.
Authors:
Originally written in C by Rich Geldreich, ported to D by ketmar.
License:
Public Domain / Unlicense - http://unlicense.org/
+/
module arsd.imageresize;
import arsd.color;
// ////////////////////////////////////////////////////////////////////////// //
// Separable filtering image rescaler v2.21, Rich Geldreich - richgel99@gmail.com
//
// This is free and unencumbered software released into the public domain.
//
// Anyone is free to copy, modify, publish, use, compile, sell, or
// distribute this software, either in source code form or as a compiled
// binary, for any purpose, commercial or non-commercial, and by any
// means.
//
// In jurisdictions that recognize copyright laws, the author or authors
// of this software dedicate any and all copyright interest in the
// software to the public domain. We make this dedication for the benefit
// of the public at large and to the detriment of our heirs and
// successors. We intend this dedication to be an overt act of
// relinquishment in perpetuity of all present and future rights to this
// software under copyright law.
//
// 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 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.
//
// For more information, please refer to <http://unlicense.org/>
//
// Feb. 1996: Creation, losely based on a heavily bugfixed version of Schumacher's resampler in Graphics Gems 3.
// Oct. 2000: Ported to C++, tweaks.
// May 2001: Continous to discrete mapping, box filter tweaks.
// March 9, 2002: Kaiser filter grabbed from Jonathan Blow's GD magazine mipmap sample code.
// Sept. 8, 2002: Comments cleaned up a bit.
// Dec. 31, 2008: v2.2: Bit more cleanup, released as public domain.
// June 4, 2012: v2.21: Switched to unlicense.org, integrated GCC fixes supplied by Peter Nagy <petern@crytek.com>, Anteru at anteru.net, and clay@coge.net,
// added Codeblocks project (for testing with MinGW and GCC), VS2008 static code analysis pass.
// float or double
private:
//version = iresample_debug;
// ////////////////////////////////////////////////////////////////////////// //
public enum ImageResizeDefaultFilter = "lanczos4"; /// Default filter for image resampler.
public enum ImageResizeMaxDimension = 65536; /// Maximum image width/height for image resampler.
// ////////////////////////////////////////////////////////////////////////// //
/// Number of known image resizer filters.
public @property int imageResizeFilterCount () { pragma(inline, true); return NumFilters; }
/// Get filter name. Will return `null` for invalid index.
public string imageResizeFilterName (long idx) { pragma(inline, true); return (idx >= 0 && idx < NumFilters ? gFilters.ptr[cast(uint)idx].name : null); }
/// Find filter index by name. Will use default filter for invalid names.
public int imageResizeFindFilter (const(char)[] name, const(char)[] defaultFilter=ImageResizeDefaultFilter) {
int res = resamplerFindFilterInternal(name);
if (res >= 0) return res;
res = resamplerFindFilterInternal(defaultFilter);
if (res >= 0) return res;
res = resamplerFindFilterInternal("lanczos4");
assert(res >= 0);
return res;
}
/++
Calculates a new size that fits inside the maximums while keeping the original aspect ratio.
History:
Added March 18, 2021 (dub v9.4)
+/
public Size calculateSizeKeepingAspectRatio(int currentWidth, int currentHeight, int maxWidth, int maxHeight) {
if(currentWidth <= maxWidth && currentHeight <= maxHeight)
return Size(currentWidth, currentHeight);
float shrinkage = 1.0;
if(currentWidth > maxWidth) {
shrinkage = cast(float) maxWidth / currentWidth;
}
if(currentHeight > maxHeight) {
auto shrinkage2 = cast(float) maxHeight / currentHeight;
if(shrinkage2 < shrinkage)
shrinkage = shrinkage2;
}
return Size(cast(int) (currentWidth * shrinkage), cast(int) (currentHeight * shrinkage));
}
// ////////////////////////////////////////////////////////////////////////// //
/// Resize image.
public TrueColorImage imageResize(int Components=4) (MemoryImage msrcimg, int dstwdt, int dsthgt, const(char)[] filter=null, float gamma=1.0f, float filterScale=1.0f) {
static assert(Components == 1 || Components == 3 || Components == 4, "invalid number of components in color");
return imageResize!Components(msrcimg, dstwdt, dsthgt, imageResizeFindFilter(filter), gamma, filterScale);
}
/// ditto
public TrueColorImage imageResize(int Components=4) (MemoryImage msrcimg, int dstwdt, int dsthgt, int filter, float gamma=1.0f, float filterScale=1.0f) {
static assert(Components == 1 || Components == 3 || Components == 4, "invalid number of components in color");
if (msrcimg is null || msrcimg.width < 1 || msrcimg.height < 1 || msrcimg.width > ImageResizeMaxDimension || msrcimg.height > ImageResizeMaxDimension) {
throw new Exception("invalid source image");
}
if (dstwdt < 1 || dsthgt < 1 || dstwdt > ImageResizeMaxDimension || dsthgt > ImageResizeMaxDimension) throw new Exception("invalid destination image size");
auto resimg = new TrueColorImage(dstwdt, dsthgt);
scope(failure) .destroy(resimg);
if (auto tc = cast(TrueColorImage)msrcimg) {
imageResize!Components(
delegate (Color[] destrow, int y) { destrow[] = tc.imageData.colors[y*tc.width..(y+1)*tc.width]; },
delegate (int y, const(Color)[] row) { resimg.imageData.colors[y*resimg.width..(y+1)*resimg.width] = row[]; },
msrcimg.width, msrcimg.height, dstwdt, dsthgt, filter, gamma, filterScale
);
} else {
imageResize!Components(
delegate (Color[] destrow, int y) { foreach (immutable x, ref c; destrow) c = msrcimg.getPixel(cast(int)x, y); },
delegate (int y, const(Color)[] row) { resimg.imageData.colors[y*resimg.width..(y+1)*resimg.width] = row[]; },
msrcimg.width, msrcimg.height, dstwdt, dsthgt, filter, gamma, filterScale
);
}
return resimg;
}
private {
enum Linear2srgbTableSize = 4096;
enum InvLinear2srgbTableSize = cast(float)(1.0f/Linear2srgbTableSize);
float[256] srgb2linear = void;
ubyte[Linear2srgbTableSize] linear2srgb = void;
float lastGamma = float.nan;
}
/// Resize image.
/// Partial gamma correction looks better on mips; set to 1.0 to disable gamma correction.
/// Filter scale: values < 1.0 cause aliasing, but create sharper looking mips (0.75f, for example).
public void imageResize(int Components=4) (
scope void delegate (Color[] destrow, int y) srcGetRow,
scope void delegate (int y, const(Color)[] row) dstPutRow,
int srcwdt, int srchgt, int dstwdt, int dsthgt,
int filter=-1, float gamma=1.0f, float filterScale=1.0f
) {
static assert(Components == 1 || Components == 3 || Components == 4, "invalid number of components in color");
assert(srcGetRow !is null);
assert(dstPutRow !is null);
if (srcwdt < 1 || srchgt < 1 || dstwdt < 1 || dsthgt < 1 ||
srcwdt > ImageResizeMaxDimension || srchgt > ImageResizeMaxDimension ||
dstwdt > ImageResizeMaxDimension || dsthgt > ImageResizeMaxDimension) throw new Exception("invalid image size");
if (filter < 0 || filter >= NumFilters) {
filter = resamplerFindFilterInternal(ImageResizeDefaultFilter);
if (filter < 0) {
filter = resamplerFindFilterInternal("lanczos4");
}
}
assert(filter >= 0 && filter < NumFilters);
if (lastGamma != gamma) {
version(iresample_debug) { import core.stdc.stdio; stderr.fprintf("creating translation tables for gamma %f (previous gamma is %f)\n", gamma, lastGamma); }
foreach (immutable i, ref v; srgb2linear[]) {
import std.math : pow;
v = cast(float)pow(cast(int)i*1.0f/255.0f, gamma);
}
immutable float invSourceGamma = 1.0f/gamma;
foreach (immutable i, ref v; linear2srgb[]) {
import std.math : pow;
int k = cast(int)(255.0f*pow(cast(int)i*InvLinear2srgbTableSize, invSourceGamma)+0.5f);
if (k < 0) k = 0; else if (k > 255) k = 255;
v = cast(ubyte)k;
}
lastGamma = gamma;
}
version(iresample_debug) { import core.stdc.stdio; stderr.fprintf("filter is %d\n", filter); }
ImageResampleWorker[Components] resamplers;
float[][Components] samples;
Color[] srcrow, dstrow;
scope(exit) {
foreach (ref rsm; resamplers[]) .destroy(rsm);
foreach (ref smr; samples[]) .destroy(smr);
}
// now create a ImageResampleWorker instance for each component to process
// the first instance will create new contributor tables, which are shared by the resamplers
// used for the other components (a memory and slight cache efficiency optimization).
resamplers[0] = new ImageResampleWorker(srcwdt, srchgt, dstwdt, dsthgt, ImageResampleWorker.BoundaryClamp, 0.0f, 1.0f, filter, null, null, filterScale, filterScale);
samples[0].length = srcwdt;
srcrow.length = srcwdt;
dstrow.length = dstwdt;
foreach (immutable i; 1..Components) {
resamplers[i] = new ImageResampleWorker(srcwdt, srchgt, dstwdt, dsthgt, ImageResampleWorker.BoundaryClamp, 0.0f, 1.0f, filter, resamplers[0].getClistX(), resamplers[0].getClistY(), filterScale, filterScale);
samples[i].length = srcwdt;
}
int dsty = 0;
foreach (immutable int srcy; 0..srchgt) {
// get row components
srcGetRow(srcrow, srcy);
{
auto scp = srcrow.ptr;
foreach (immutable x; 0..srcwdt) {
auto sc = *scp++;
samples.ptr[0].ptr[x] = srgb2linear.ptr[sc.r]; // first component
static if (Components > 1) samples.ptr[1].ptr[x] = srgb2linear.ptr[sc.g]; // second component
static if (Components > 2) samples.ptr[2].ptr[x] = srgb2linear.ptr[sc.b]; // thirs component
static if (Components == 4) samples.ptr[3].ptr[x] = sc.a*(1.0f/255.0f); // fourth component is alpha, and it is already linear
}
}
foreach (immutable c; 0..Components) if (!resamplers.ptr[c].putLine(samples.ptr[c].ptr)) assert(0, "out of memory");
for (;;) {
int compIdx = 0;
for (; compIdx < Components; ++compIdx) {
const(float)* outsmp = resamplers.ptr[compIdx].getLine();
if (outsmp is null) break;
auto dsc = dstrow.ptr;
// alpha?
static if (Components == 4) {
if (compIdx == 3) {
foreach (immutable x; 0..dstwdt) {
dsc.a = Color.clampToByte(cast(int)(255.0f*(*outsmp++)+0.5f));
++dsc;
}
continue;
}
}
// color
auto dsb = (cast(ubyte*)dsc)+compIdx;
foreach (immutable x; 0..dstwdt) {
int j = cast(int)(Linear2srgbTableSize*(*outsmp++)+0.5f);
if (j < 0) j = 0; else if (j >= Linear2srgbTableSize) j = Linear2srgbTableSize-1;
*dsb = linear2srgb.ptr[j];
dsb += 4;
}
}
if (compIdx < Components) break;
// fill destination line
assert(dsty < dsthgt);
static if (Components != 4) {
auto dsc = dstrow.ptr;
foreach (immutable x; 0..dstwdt) {
static if (Components == 1) dsc.g = dsc.b = dsc.r;
dsc.a = 255;
++dsc;
}
}
//version(iresample_debug) { import core.stdc.stdio; stderr.fprintf("writing dest row %d with %u components\n", dsty, Components); }
dstPutRow(dsty, dstrow);
++dsty;
}
}
}
// ////////////////////////////////////////////////////////////////////////// //
public final class ImageResampleWorker {
nothrow @trusted @nogc:
public:
alias ResampleReal = float;
alias Sample = ResampleReal;
static struct Contrib {
ResampleReal weight;
ushort pixel;
}
static struct ContribList {
ushort n;
Contrib* p;
}
alias BoundaryOp = int;
enum /*Boundary_Op*/ {
BoundaryWrap = 0,
BoundaryReflect = 1,
BoundaryClamp = 2,
}
alias Status = int;
enum /*Status*/ {
StatusOkay = 0,
StatusOutOfMemory = 1,
StatusBadFilterName = 2,
StatusScanBufferFull = 3,
}
private:
alias FilterFunc = ResampleReal function (ResampleReal) nothrow @trusted @nogc;
int mIntermediateX;
int mResampleSrcX;
int mResampleSrcY;
int mResampleDstX;
int mResampleDstY;
BoundaryOp mBoundaryOp;
Sample* mPdstBuf;
Sample* mPtmpBuf;
ContribList* mPclistX;
ContribList* mPclistY;
bool mClistXForced;
bool mClistYForced;
bool mDelayXResample;
int* mPsrcYCount;
ubyte* mPsrcYFlag;
// The maximum number of scanlines that can be buffered at one time.
enum MaxScanBufSize = ImageResizeMaxDimension;
static struct ScanBuf {
int[MaxScanBufSize] scanBufY;
Sample*[MaxScanBufSize] scanBufL;
}
ScanBuf* mPscanBuf;
int mCurSrcY;
int mCurDstY;
Status mStatus;
// The make_clist() method generates, for all destination samples,
// the list of all source samples with non-zero weighted contributions.
ContribList* makeClist(
int srcX, int dstX, BoundaryOp boundaryOp,
FilterFunc Pfilter,
ResampleReal filterSupport,
ResampleReal filterScale,
ResampleReal srcOfs)
{
import core.stdc.stdlib : calloc, free;
import std.math : floor, ceil;
static struct ContribBounds {
// The center of the range in DISCRETE coordinates (pixel center = 0.0f).
ResampleReal center;
int left, right;
}
ContribList* Pcontrib, PcontribRes;
Contrib* Pcpool;
Contrib* PcpoolNext;
ContribBounds* PcontribBounds;
if ((Pcontrib = cast(ContribList*)calloc(dstX, ContribList.sizeof)) is null) return null;
scope(exit) if (Pcontrib !is null) free(Pcontrib);
PcontribBounds = cast(ContribBounds*)calloc(dstX, ContribBounds.sizeof);
if (PcontribBounds is null) return null;
scope(exit) free(PcontribBounds);
enum ResampleReal NUDGE = 0.5f;
immutable ResampleReal ooFilterScale = 1.0f/filterScale;
immutable ResampleReal xscale = dstX/cast(ResampleReal)srcX;
if (xscale < 1.0f) {
int total = 0;
// Handle case when there are fewer destination samples than source samples (downsampling/minification).
// stretched half width of filter
immutable ResampleReal halfWidth = (filterSupport/xscale)*filterScale;
// Find the range of source sample(s) that will contribute to each destination sample.
foreach (immutable i; 0..dstX) {
// Convert from discrete to continuous coordinates, scale, then convert back to discrete.
ResampleReal center = (cast(ResampleReal)i+NUDGE)/xscale;
center -= NUDGE;
center += srcOfs;
immutable int left = castToInt(cast(ResampleReal)floor(center-halfWidth));
immutable int right = castToInt(cast(ResampleReal)ceil(center+halfWidth));
PcontribBounds[i].center = center;
PcontribBounds[i].left = left;
PcontribBounds[i].right = right;
total += (right-left+1);
}
// Allocate memory for contributors.
if (total == 0 || ((Pcpool = cast(Contrib*)calloc(total, Contrib.sizeof)) is null)) return null;
//scope(failure) free(Pcpool);
//immutable int total = n;
PcpoolNext = Pcpool;
// Create the list of source samples which contribute to each destination sample.
foreach (immutable i; 0..dstX) {
int maxK = -1;
ResampleReal maxW = -1e+20f;
ResampleReal center = PcontribBounds[i].center;
immutable int left = PcontribBounds[i].left;
immutable int right = PcontribBounds[i].right;
Pcontrib[i].n = 0;
Pcontrib[i].p = PcpoolNext;
PcpoolNext += (right-left+1);
assert(PcpoolNext-Pcpool <= total);
ResampleReal totalWeight0 = 0;
foreach (immutable j; left..right+1) totalWeight0 += Pfilter((center-cast(ResampleReal)j)*xscale*ooFilterScale);
immutable ResampleReal norm = cast(ResampleReal)(1.0f/totalWeight0);
ResampleReal totalWeight1 = 0;
foreach (immutable j; left..right+1) {
immutable ResampleReal weight = Pfilter((center-cast(ResampleReal)j)*xscale*ooFilterScale)*norm;
if (weight == 0.0f) continue;
immutable int n = reflect(j, srcX, boundaryOp);
// Increment the number of source samples which contribute to the current destination sample.
immutable int k = Pcontrib[i].n++;
Pcontrib[i].p[k].pixel = cast(ushort)(n); // store src sample number
Pcontrib[i].p[k].weight = weight; // store src sample weight
totalWeight1 += weight; // total weight of all contributors
if (weight > maxW) {
maxW = weight;
maxK = k;
}
}
//assert(Pcontrib[i].n);
//assert(max_k != -1);
if (maxK == -1 || Pcontrib[i].n == 0) return null;
if (totalWeight1 != 1.0f) Pcontrib[i].p[maxK].weight += 1.0f-totalWeight1;
}
} else {
int total = 0;
// Handle case when there are more destination samples than source samples (upsampling).
immutable ResampleReal halfWidth = filterSupport*filterScale;
// Find the source sample(s) that contribute to each destination sample.
foreach (immutable i; 0..dstX) {
// Convert from discrete to continuous coordinates, scale, then convert back to discrete.
ResampleReal center = (cast(ResampleReal)i+NUDGE)/xscale;
center -= NUDGE;
center += srcOfs;
immutable int left = castToInt(cast(ResampleReal)floor(center-halfWidth));
immutable int right = castToInt(cast(ResampleReal)ceil(center+halfWidth));
PcontribBounds[i].center = center;
PcontribBounds[i].left = left;
PcontribBounds[i].right = right;
total += (right-left+1);
}
// Allocate memory for contributors.
if (total == 0 || ((Pcpool = cast(Contrib*)calloc(total, Contrib.sizeof)) is null)) return null;
//scope(failure) free(Pcpool);
PcpoolNext = Pcpool;
// Create the list of source samples which contribute to each destination sample.
foreach (immutable i; 0..dstX) {
int maxK = -1;
ResampleReal maxW = -1e+20f;
ResampleReal center = PcontribBounds[i].center;
immutable int left = PcontribBounds[i].left;
immutable int right = PcontribBounds[i].right;
Pcontrib[i].n = 0;
Pcontrib[i].p = PcpoolNext;
PcpoolNext += (right-left+1);
assert(PcpoolNext-Pcpool <= total);
ResampleReal totalWeight0 = 0;
foreach (immutable j; left..right+1) totalWeight0 += Pfilter((center-cast(ResampleReal)j)*ooFilterScale);
immutable ResampleReal norm = cast(ResampleReal)(1.0f/totalWeight0);
ResampleReal totalWeight1 = 0;
foreach (immutable j; left..right+1) {
immutable ResampleReal weight = Pfilter((center-cast(ResampleReal)j)*ooFilterScale)*norm;
if (weight == 0.0f) continue;
immutable int n = reflect(j, srcX, boundaryOp);
// Increment the number of source samples which contribute to the current destination sample.
immutable int k = Pcontrib[i].n++;
Pcontrib[i].p[k].pixel = cast(ushort)(n); // store src sample number
Pcontrib[i].p[k].weight = weight; // store src sample weight
totalWeight1 += weight; // total weight of all contributors
if (weight > maxW) {
maxW = weight;
maxK = k;
}
}
//assert(Pcontrib[i].n);
//assert(max_k != -1);
if (maxK == -1 || Pcontrib[i].n == 0) return null;
if (totalWeight1 != 1.0f) Pcontrib[i].p[maxK].weight += 1.0f-totalWeight1;
}
}
// don't free return value
PcontribRes = Pcontrib;
Pcontrib = null;
return PcontribRes;
}
static int countOps (const(ContribList)* Pclist, int k) {
int t = 0;
foreach (immutable i; 0..k) t += Pclist[i].n;
return t;
}
private ResampleReal mLo;
private ResampleReal mHi;
ResampleReal clampSample (ResampleReal f) const {
pragma(inline, true);
if (f < mLo) f = mLo; else if (f > mHi) f = mHi;
return f;
}
public:
// src_x/src_y - Input dimensions
// dst_x/dst_y - Output dimensions
// boundary_op - How to sample pixels near the image boundaries
// sample_low/sample_high - Clamp output samples to specified range, or disable clamping if sample_low >= sample_high
// Pclist_x/Pclist_y - Optional pointers to contributor lists from another instance of a ImageResampleWorker
// src_x_ofs/src_y_ofs - Offset input image by specified amount (fractional values okay)
this(
int srcX, int srcY,
int dstX, int dstY,
BoundaryOp boundaryOp=BoundaryClamp,
ResampleReal sampleLow=0.0f, ResampleReal sampleHigh=0.0f,
int PfilterIndex=-1,
ContribList* PclistX=null,
ContribList* PclistY=null,
ResampleReal filterXScale=1.0f,
ResampleReal filterYScale=1.0f,
ResampleReal srcXOfs=0.0f,
ResampleReal srcYOfs=0.0f)
{
import core.stdc.stdlib : calloc, malloc;
int i, j;
ResampleReal support;
FilterFunc func;
assert(srcX > 0);
assert(srcY > 0);
assert(dstX > 0);
assert(dstY > 0);
mLo = sampleLow;
mHi = sampleHigh;
mDelayXResample = false;
mIntermediateX = 0;
mPdstBuf = null;
mPtmpBuf = null;
mClistXForced = false;
mPclistX = null;
mClistYForced = false;
mPclistY = null;
mPsrcYCount = null;
mPsrcYFlag = null;
mPscanBuf = null;
mStatus = StatusOkay;
mResampleSrcX = srcX;
mResampleSrcY = srcY;
mResampleDstX = dstX;
mResampleDstY = dstY;
mBoundaryOp = boundaryOp;
if ((mPdstBuf = cast(Sample*)malloc(mResampleDstX*Sample.sizeof)) is null) {
mStatus = StatusOutOfMemory;
return;
}
if (PfilterIndex < 0 || PfilterIndex >= NumFilters) {
PfilterIndex = resamplerFindFilterInternal(ImageResizeDefaultFilter);
if (PfilterIndex < 0 || PfilterIndex >= NumFilters) {
mStatus = StatusBadFilterName;
return;
}
}
func = gFilters[PfilterIndex].func;
support = gFilters[PfilterIndex].support;
// Create contributor lists, unless the user supplied custom lists.
if (PclistX is null) {
mPclistX = makeClist(mResampleSrcX, mResampleDstX, mBoundaryOp, func, support, filterXScale, srcXOfs);
if (mPclistX is null) {
mStatus = StatusOutOfMemory;
return;
}
} else {
mPclistX = PclistX;
mClistXForced = true;
}
if (PclistY is null) {
mPclistY = makeClist(mResampleSrcY, mResampleDstY, mBoundaryOp, func, support, filterYScale, srcYOfs);
if (mPclistY is null) {
mStatus = StatusOutOfMemory;
return;
}
} else {
mPclistY = PclistY;
mClistYForced = true;
}
if ((mPsrcYCount = cast(int*)calloc(mResampleSrcY, int.sizeof)) is null) {
mStatus = StatusOutOfMemory;
return;
}
if ((mPsrcYFlag = cast(ubyte*)calloc(mResampleSrcY, ubyte.sizeof)) is null) {
mStatus = StatusOutOfMemory;
return;
}
// Count how many times each source line contributes to a destination line.
for (i = 0; i < mResampleDstY; ++i) {
for (j = 0; j < mPclistY[i].n; ++j) {
++mPsrcYCount[resamplerRangeCheck(mPclistY[i].p[j].pixel, mResampleSrcY)];
}
}
if ((mPscanBuf = cast(ScanBuf*)malloc(ScanBuf.sizeof)) is null) {
mStatus = StatusOutOfMemory;
return;
}
for (i = 0; i < MaxScanBufSize; ++i) {
mPscanBuf.scanBufY.ptr[i] = -1;
mPscanBuf.scanBufL.ptr[i] = null;
}
mCurSrcY = mCurDstY = 0;
{
// Determine which axis to resample first by comparing the number of multiplies required
// for each possibility.
int xOps = countOps(mPclistX, mResampleDstX);
int yOps = countOps(mPclistY, mResampleDstY);
// Hack 10/2000: Weight Y axis ops a little more than X axis ops.
// (Y axis ops use more cache resources.)
int xyOps = xOps*mResampleSrcY+(4*yOps*mResampleDstX)/3;
int yxOps = (4*yOps*mResampleSrcX)/3+xOps*mResampleDstY;
// Now check which resample order is better. In case of a tie, choose the order
// which buffers the least amount of data.
if (xyOps > yxOps || (xyOps == yxOps && mResampleSrcX < mResampleDstX)) {
mDelayXResample = true;
mIntermediateX = mResampleSrcX;
} else {
mDelayXResample = false;
mIntermediateX = mResampleDstX;
}
}
if (mDelayXResample) {
if ((mPtmpBuf = cast(Sample*)malloc(mIntermediateX*Sample.sizeof)) is null) {
mStatus = StatusOutOfMemory;
return;
}
}
}
~this () {
import core.stdc.stdlib : free;
if (mPdstBuf !is null) {
free(mPdstBuf);
mPdstBuf = null;
}
if (mPtmpBuf !is null) {
free(mPtmpBuf);
mPtmpBuf = null;
}
// Don't deallocate a contibutor list if the user passed us one of their own.
if (mPclistX !is null && !mClistXForced) {
free(mPclistX.p);
free(mPclistX);
mPclistX = null;
}
if (mPclistY !is null && !mClistYForced) {
free(mPclistY.p);
free(mPclistY);
mPclistY = null;
}
if (mPsrcYCount !is null) {
free(mPsrcYCount);
mPsrcYCount = null;
}
if (mPsrcYFlag !is null) {
free(mPsrcYFlag);
mPsrcYFlag = null;
}
if (mPscanBuf !is null) {
foreach (immutable i; 0..MaxScanBufSize) if (mPscanBuf.scanBufL.ptr[i] !is null) free(mPscanBuf.scanBufL.ptr[i]);
free(mPscanBuf);
mPscanBuf = null;
}
}
// Reinits resampler so it can handle another frame.
void restart () {
import core.stdc.stdlib : free;
if (StatusOkay != mStatus) return;
mCurSrcY = mCurDstY = 0;
foreach (immutable i; 0..mResampleSrcY) {
mPsrcYCount[i] = 0;
mPsrcYFlag[i] = false;
}
foreach (immutable i; 0..mResampleDstY) {
foreach (immutable j; 0..mPclistY[i].n) {
++mPsrcYCount[resamplerRangeCheck(mPclistY[i].p[j].pixel, mResampleSrcY)];
}
}
foreach (immutable i; 0..MaxScanBufSize) {
mPscanBuf.scanBufY.ptr[i] = -1;
free(mPscanBuf.scanBufL.ptr[i]);
mPscanBuf.scanBufL.ptr[i] = null;
}
}
// false on out of memory.
bool putLine (const(Sample)* Psrc) {
int i;
if (mCurSrcY >= mResampleSrcY) return false;
// Does this source line contribute to any destination line? if not, exit now.
if (!mPsrcYCount[resamplerRangeCheck(mCurSrcY, mResampleSrcY)]) {
++mCurSrcY;
return true;
}
// Find an empty slot in the scanline buffer. (FIXME: Perf. is terrible here with extreme scaling ratios.)
for (i = 0; i < MaxScanBufSize; ++i) if (mPscanBuf.scanBufY.ptr[i] == -1) break;
// If the buffer is full, exit with an error.
if (i == MaxScanBufSize) {
mStatus = StatusScanBufferFull;
return false;
}
mPsrcYFlag[resamplerRangeCheck(mCurSrcY, mResampleSrcY)] = true;
mPscanBuf.scanBufY.ptr[i] = mCurSrcY;
// Does this slot have any memory allocated to it?
if (!mPscanBuf.scanBufL.ptr[i]) {
import core.stdc.stdlib : malloc;
if ((mPscanBuf.scanBufL.ptr[i] = cast(Sample*)malloc(mIntermediateX*Sample.sizeof)) is null) {
mStatus = StatusOutOfMemory;
return false;
}
}
// Resampling on the X axis first?
if (mDelayXResample) {
import core.stdc.string : memcpy;
assert(mIntermediateX == mResampleSrcX);
// Y-X resampling order
memcpy(mPscanBuf.scanBufL.ptr[i], Psrc, mIntermediateX*Sample.sizeof);
} else {
assert(mIntermediateX == mResampleDstX);
// X-Y resampling order
resampleX(mPscanBuf.scanBufL.ptr[i], Psrc);
}
++mCurSrcY;
return true;
}
// null if no scanlines are currently available (give the resampler more scanlines!)
const(Sample)* getLine () {
// if all the destination lines have been generated, then always return null
if (mCurDstY == mResampleDstY) return null;
// check to see if all the required contributors are present, if not, return null
foreach (immutable i; 0..mPclistY[mCurDstY].n) {
if (!mPsrcYFlag[resamplerRangeCheck(mPclistY[mCurDstY].p[i].pixel, mResampleSrcY)]) return null;
}
resampleY(mPdstBuf);
++mCurDstY;
return mPdstBuf;
}
@property Status status () const { pragma(inline, true); return mStatus; }
// returned contributor lists can be shared with another ImageResampleWorker
void getClists (ContribList** ptrClistX, ContribList** ptrClistY) {
if (ptrClistX !is null) *ptrClistX = mPclistX;
if (ptrClistY !is null) *ptrClistY = mPclistY;
}
@property ContribList* getClistX () { pragma(inline, true); return mPclistX; }
@property ContribList* getClistY () { pragma(inline, true); return mPclistY; }
// filter accessors
static @property auto filters () {
static struct FilterRange {
pure nothrow @trusted @nogc:
int idx;
@property bool empty () const { pragma(inline, true); return (idx >= NumFilters); }
@property string front () const { pragma(inline, true); return (idx < NumFilters ? gFilters[idx].name : null); }
void popFront () { if (idx < NumFilters) ++idx; }
int length () const { return cast(int)NumFilters; }
alias opDollar = length;
}
return FilterRange();
}
private:
/* Ensure that the contributing source sample is
* within bounds. If not, reflect, clamp, or wrap.
*/
int reflect (in int j, in int srcX, in BoundaryOp boundaryOp) {
int n;
if (j < 0) {
if (boundaryOp == BoundaryReflect) {
n = -j;
if (n >= srcX) n = srcX-1;
} else if (boundaryOp == BoundaryWrap) {
n = posmod(j, srcX);
} else {
n = 0;
}
} else if (j >= srcX) {
if (boundaryOp == BoundaryReflect) {
n = (srcX-j)+(srcX-1);
if (n < 0) n = 0;
} else if (boundaryOp == BoundaryWrap) {
n = posmod(j, srcX);
} else {
n = srcX-1;
}
} else {
n = j;
}
return n;
}
void resampleX (Sample* Pdst, const(Sample)* Psrc) {
assert(Pdst);
assert(Psrc);
Sample total;
ContribList *Pclist = mPclistX;
Contrib *p;
for (int i = mResampleDstX; i > 0; --i, ++Pclist) {
int j = void;
for (j = Pclist.n, p = Pclist.p, total = 0; j > 0; --j, ++p) total += Psrc[p.pixel]*p.weight;
*Pdst++ = total;
}
}
void scaleYMov (Sample* Ptmp, const(Sample)* Psrc, ResampleReal weight, int dstX) {
// Not += because temp buf wasn't cleared.
for (int i = dstX; i > 0; --i) *Ptmp++ = *Psrc++*weight;
}
void scaleYAdd (Sample* Ptmp, const(Sample)* Psrc, ResampleReal weight, int dstX) {
for (int i = dstX; i > 0; --i) (*Ptmp++) += *Psrc++*weight;
}
void clamp (Sample* Pdst, int n) {
while (n > 0) {
*Pdst = clampSample(*Pdst);
++Pdst;
--n;
}
}
void resampleY (Sample* Pdst) {
Sample* Psrc;
ContribList* Pclist = &mPclistY[mCurDstY];
Sample* Ptmp = mDelayXResample ? mPtmpBuf : Pdst;
assert(Ptmp);
// process each contributor
foreach (immutable i; 0..Pclist.n) {
// locate the contributor's location in the scan buffer -- the contributor must always be found!
int j = void;
for (j = 0; j < MaxScanBufSize; ++j) if (mPscanBuf.scanBufY.ptr[j] == Pclist.p[i].pixel) break;
assert(j < MaxScanBufSize);
Psrc = mPscanBuf.scanBufL.ptr[j];
if (!i) {
scaleYMov(Ptmp, Psrc, Pclist.p[i].weight, mIntermediateX);
} else {
scaleYAdd(Ptmp, Psrc, Pclist.p[i].weight, mIntermediateX);
}
/* If this source line doesn't contribute to any
* more destination lines then mark the scanline buffer slot
* which holds this source line as free.
* (The max. number of slots used depends on the Y
* axis sampling factor and the scaled filter width.)
*/
if (--mPsrcYCount[resamplerRangeCheck(Pclist.p[i].pixel, mResampleSrcY)] == 0) {
mPsrcYFlag[resamplerRangeCheck(Pclist.p[i].pixel, mResampleSrcY)] = false;
mPscanBuf.scanBufY.ptr[j] = -1;
}
}
// now generate the destination line
if (mDelayXResample) {
// X was resampling delayed until after Y resampling
assert(Pdst != Ptmp);
resampleX(Pdst, Ptmp);
} else {
assert(Pdst == Ptmp);
}
if (mLo < mHi) clamp(Pdst, mResampleDstX);
}
}
// ////////////////////////////////////////////////////////////////////////// //
private nothrow @trusted @nogc:
int resamplerRangeCheck (int v, int h) {
version(assert) {
//import std.conv : to;
//assert(v >= 0 && v < h, "invalid v ("~to!string(v)~"), should be in [0.."~to!string(h)~")");
assert(v >= 0 && v < h); // alas, @nogc
return v;
} else {
pragma(inline, true);
return v;
}
}
enum M_PI = 3.14159265358979323846;
// Float to int cast with truncation.
int castToInt (ImageResampleWorker.ResampleReal i) { pragma(inline, true); return cast(int)i; }
// (x mod y) with special handling for negative x values.
int posmod (int x, int y) {
pragma(inline, true);
if (x >= 0) {
return (x%y);
} else {
int m = (-x)%y;
if (m != 0) m = y-m;
return m;
}
}
// To add your own filter, insert the new function below and update the filter table.
// There is no need to make the filter function particularly fast, because it's
// only called during initializing to create the X and Y axis contributor tables.
/* pulse/Fourier window */
enum BoxFilterSupport = 0.5f;
ImageResampleWorker.ResampleReal boxFilter (ImageResampleWorker.ResampleReal t) {
// make_clist() calls the filter function with t inverted (pos = left, neg = right)
if (t >= -0.5f && t < 0.5f) return 1.0f; else return 0.0f;
}
/* box (*) box, bilinear/triangle */
enum TentFilterSupport = 1.0f;
ImageResampleWorker.ResampleReal tentFilter (ImageResampleWorker.ResampleReal t) {
if (t < 0.0f) t = -t;
if (t < 1.0f) return 1.0f-t; else return 0.0f;
}