1 /**
2 Color type and operations. Port of ae.utils.graphics.
3
4 License:
5 This Source Code Form is subject to the terms of
6 the Mozilla Public License, v. 2.0. If a copy of
7 the MPL was not distributed with this file, You
8 can obtain one at http://mozilla.org/MPL/2.0/.
9
10 Copyright: Vladimir Panteleev <vladimir@thecybershadow.net>
11 Copyright: Guillaume Piolat <contact@auburnsounds.com>
12 */
13
14 module dplug.graphics.color;
15
16 import std.traits: Signed, isSigned, isNumeric;
17
18 import inteli.emmintrin;
19
20 import dplug.core.math;
21
22
23 /// Evaluates to array of strings with name for each field.
24 @property string[] structFields(T)()
25 if (is(T == struct) || is(T == class))
26 {
27 import std.string : split;
28
29 string[] fields;
30 foreach (i, f; T.init.tupleof)
31 {
32 string field = T.tupleof[i].stringof;
33 field = field.split(".")[$-1];
34 fields ~= field;
35 }
36 return fields;
37 }
38
39
40 T itpl(T, U)(T low, T high, U r, U rLow, U rHigh)
41 {
42 return cast(T)(low + (cast(Signed!T)high-cast(Signed!T)low) * (cast(Signed!U)r - cast(Signed!U)rLow) / (cast(Signed!U)rHigh - cast(Signed!U)rLow));
43 }
44
45 auto sqr(T)(T x) { return x*x; }
46
47
48 void sort2(T)(ref T x, ref T y)
49 {
50 if (x > y)
51 {
52 T z = x;
53 x = y;
54 y = z;
55 }
56 }
57
58 byte sign(T)(T x)
59 {
60 return x<0 ? -1 : (x>0 ? 1 : 0);
61 }
62
63 /// Integer log2.
64 private ubyte ilog2(T)(T n)
65 {
66 ubyte result = 0;
67 while (n >>= 1)
68 result++;
69 return result;
70 }
71
72 private T nextPowerOfTwo(T)(T x)
73 {
74 x |= x >> 1;
75 x |= x >> 2;
76 x |= x >> 4;
77 static if (T.sizeof > 1)
78 x |= x >> 8;
79 static if (T.sizeof > 2)
80 x |= x >> 16;
81 static if (T.sizeof > 4)
82 x |= x >> 32;
83 return x + 1;
84 }
85
86 /// Like std.typecons.Tuple, but a template mixin.
87 /// Unlike std.typecons.Tuple, names may not be omitted - but repeating types may be.
88 /// Example: FieldList!(ubyte, "r", "g", "b", ushort, "a");
89 mixin template FieldList(Fields...)
90 {
91 mixin(GenFieldList!(void, Fields));
92 }
93
94 template GenFieldList(T, Fields...)
95 {
96 static if (Fields.length == 0)
97 enum GenFieldList = "";
98 else
99 {
100 static if (is(typeof(Fields[0]) == string))
101 enum GenFieldList = T.stringof ~ " " ~ Fields[0] ~ ";\n" ~ GenFieldList!(T, Fields[1..$]);
102 else
103 enum GenFieldList = GenFieldList!(Fields[0], Fields[1..$]);
104 }
105 }
106
107 unittest
108 {
109 struct S
110 {
111 mixin FieldList!(ubyte, "r", "g", "b", ushort, "a");
112 }
113 S s;
114 static assert(is(typeof(s.r) == ubyte));
115 static assert(is(typeof(s.g) == ubyte));
116 static assert(is(typeof(s.b) == ubyte));
117 static assert(is(typeof(s.a) == ushort));
118 }
119
120
121 /// Return the number of bits used to store the value part, i.e.
122 /// T.sizeof*8 for integer parts and the mantissa size for
123 /// floating-point types.
124 template valueBits(T)
125 {
126 static if (is(T : ulong))
127 enum valueBits = T.sizeof * 8;
128 else
129 static if (is(T : real))
130 enum valueBits = T.mant_dig;
131 else
132 static assert(false, "Don't know how many value bits there are in " ~ T.stringof);
133 }
134
135 static assert(valueBits!uint == 32);
136 static assert(valueBits!double == 53);
137
138
139
140 /// Instantiates to a color type.
141 /// FieldTuple is the color specifier, as parsed by
142 /// the FieldList template from ae.utils.meta.
143 /// By convention, each field's name indicates its purpose:
144 /// - x: padding
145 /// - a: alpha
146 /// - l: lightness (or grey, for monochrome images)
147 /// - others (r, g, b, etc.): color information
148
149 // MAYDO: figure out if we need all these methods in the color type itself
150 // - code such as gamma conversion needs to create color types
151 // - ReplaceType can't copy methods
152 // - even if we move out all conventional methods, that still leaves operator overloading
153
154 struct DefColor(FieldTuple...)
155 {
156 alias Spec = FieldTuple;
157 mixin FieldList!FieldTuple;
158
159 // A "dumb" type to avoid cyclic references.
160 private struct Fields { mixin FieldList!FieldTuple; }
161
162 /// Whether or not all channel fields have the same base type.
163 // Only "true" supported for now, may change in the future (e.g. for 5:6:5)
164 enum homogenous = true;
165
166 /// The number of fields in this color type.
167 enum channels = Fields.init.tupleof.length;
168
169 static if (homogenous)
170 {
171 alias ChannelType = typeof(Fields.init.tupleof[0]);
172 enum channelBits = valueBits!ChannelType;
173 }
174
175 /// Return a Color instance with all fields set to "value".
176 static typeof(this) monochrome(ChannelType value)
177 {
178 typeof(this) r;
179 foreach (i, f; r.tupleof)
180 r.tupleof[i] = value;
181 return r;
182 }
183
184 /// Interpolate between two colors.
185 static typeof(this) itpl(P)(typeof(this) c0, typeof(this) c1, P p, P p0, P p1)
186 {
187 alias ExpandNumericType!(ChannelType, P.sizeof*8) U;
188 alias Signed!U S;
189 typeof(this) r;
190 foreach (i, f; r.tupleof)
191 static if (r.tupleof[i].stringof != "r.x") // skip padding
192 r.tupleof[i] = cast(ChannelType).itpl(cast(U)c0.tupleof[i], cast(U)c1.tupleof[i], cast(S)p, cast(S)p0, cast(S)p1);
193 return r;
194 }
195
196 /// Construct an RGB color from a typical hex string.
197 static if (is(typeof(this.r) == ubyte) && is(typeof(this.g) == ubyte) && is(typeof(this.b) == ubyte))
198 {
199 static typeof(this) fromHex(in char[] s)
200 {
201 import std.conv;
202 import std.exception;
203
204 enforce(s.length == 6, "Invalid color string");
205 typeof(this) c;
206 c.r = s[0..2].to!ubyte(16);
207 c.g = s[2..4].to!ubyte(16);
208 c.b = s[4..6].to!ubyte(16);
209 return c;
210 }
211
212 string toHex() const
213 {
214 import std.string;
215 return format("%02X%02X%02X", r, g, b);
216 }
217 }
218
219 /// Warning: overloaded operators preserve types and may cause overflows
220 typeof(this) opUnary(string op)()
221 if (op=="~" || op=="-")
222 {
223 typeof(this) r;
224 foreach (i, f; r.tupleof)
225 static if(r.tupleof[i].stringof != "r.x") // skip padding
226 r.tupleof[i] = cast(typeof(r.tupleof[i])) mixin(op ~ `this.tupleof[i]`);
227 return r;
228 }
229
230 /// ditto
231 typeof(this) opOpAssign(string op)(int o)
232 {
233 foreach (i, f; this.tupleof)
234 static if(this.tupleof[i].stringof != "this.x") // skip padding
235 this.tupleof[i] = cast(typeof(this.tupleof[i])) mixin(`this.tupleof[i]` ~ op ~ `=o`);
236 return this;
237 }
238
239 /// ditto
240 typeof(this) opOpAssign(string op, T)(T o)
241 if (is(T==struct) && structFields!T == structFields!Fields)
242 {
243 foreach (i, f; this.tupleof)
244 static if(this.tupleof[i].stringof != "this.x") // skip padding
245 this.tupleof[i] = cast(typeof(this.tupleof[i])) mixin(`this.tupleof[i]` ~ op ~ `=o.tupleof[i]`);
246 return this;
247 }
248
249 /// ditto
250 typeof(this) opBinary(string op, T)(T o)
251 if (op != "~")
252 {
253 auto r = this;
254 mixin("r" ~ op ~ "=o;");
255 return r;
256 }
257
258 /// Apply a custom operation for each channel. Example:
259 /// COLOR.op!q{(a + b) / 2}(colorA, colorB);
260 static typeof(this) op(string expr, T...)(T values)
261 {
262 static assert(values.length <= 10);
263
264 string genVars(string channel)
265 {
266 string result;
267 foreach (j, Tj; T)
268 {
269 static if (is(Tj == struct)) // TODO: tighter constraint (same color channels)?
270 result ~= "auto " ~ cast(char)('a' + j) ~ " = values[" ~ cast(char)('0' + j) ~ "]." ~ channel ~ ";\n";
271 else
272 result ~= "auto " ~ cast(char)('a' + j) ~ " = values[" ~ cast(char)('0' + j) ~ "];\n";
273 }
274 return result;
275 }
276
277 typeof(this) r;
278 foreach (i, f; r.tupleof)
279 {
280 mixin(genVars(r.tupleof[i].stringof[2..$]));
281 r.tupleof[i] = mixin(expr);
282 }
283 return r;
284 }
285
286 T opCast(T)()
287 if (is(T==struct) && structFields!T == structFields!Fields)
288 {
289 T t;
290 foreach (i, f; this.tupleof)
291 t.tupleof[i] = cast(typeof(t.tupleof[i])) this.tupleof[i];
292 return t;
293 }
294
295 /// Sum of all channels
296 ExpandIntegerType!(ChannelType, ilog2(nextPowerOfTwo(channels))) sum()
297 {
298 typeof(return) result;
299 foreach (i, f; this.tupleof)
300 static if (this.tupleof[i].stringof != "this.x") // skip padding
301 result += this.tupleof[i];
302 return result;
303 }
304 }
305
306 // The "x" has the special meaning of "padding" and is ignored in some circumstances
307 alias DefColor!(ubyte , "r", "g", "b" ) RGB ;
308 alias DefColor!(ubyte , "r", "g", "b", "a") RGBA ;
309 alias DefColor!(ushort , "r", "g", "b", "a") RGBA16 ;
310
311
312 alias DefColor!(ubyte , "l" ) L8 ;
313 alias DefColor!(ushort , "l" ) L16 ;
314 alias DefColor!(float , "l" ) L32f ;
315
316 alias DefColor!(float , "r", "g", "b" ) RGBf ;
317 alias DefColor!(float , "r", "g", "b", "a") RGBAf ;
318
319 static assert(L32f.sizeof == 4);
320 static assert(RGBf.sizeof == 12);
321 static assert(RGBAf.sizeof == 16);
322
323 unittest
324 {
325 static assert(RGB.sizeof == 3);
326 RGB[2] arr;
327 static assert(arr.sizeof == 6);
328
329 RGB hex = RGB.fromHex("123456");
330 assert(hex.r == 0x12 && hex.g == 0x34 && hex.b == 0x56);
331
332 assert(RGB(1, 2, 3) + RGB(4, 5, 6) == RGB(5, 7, 9));
333
334 RGB c = RGB(1, 1, 1);
335 c += 1;
336 assert(c == RGB(2, 2, 2));
337 c += c;
338 assert(c == RGB(4, 4, 4));
339 }
340
341 unittest
342 {
343 import std.conv;
344
345 L8 r;
346
347 r = L8.itpl(L8(100), L8(200), 15, 10, 20);
348 assert(r == L8(150), text(r));
349 }
350
351
352 unittest
353 {
354 DefColor!(real, "r", "g", "b") c;
355 }
356
357 /// Obtains the type of each channel for homogenous colors.
358 template ChannelType(T)
359 {
360 static if (is(T == struct))
361 alias ChannelType = T.ChannelType;
362 else
363 alias ChannelType = T;
364 }
365
366 /// Resolves to a Color instance with a different ChannelType.
367 template ChangeChannelType(COLOR, T)
368 if (isNumeric!COLOR)
369 {
370 alias ChangeChannelType = T;
371 }
372
373 /// ditto
374 template ChangeChannelType(COLOR, T)
375 if (is(COLOR : DefColor!Spec, Spec...))
376 {
377 static assert(COLOR.homogenous, "Can't change ChannelType of non-homogenous Color");
378 alias ChangeChannelType = DefColor!(T, COLOR.Spec[1..$]);
379 }
380
381 static assert(is(ChangeChannelType!(int, ushort) == ushort));
382
383
384 /// Expand to a built-in numeric type of the same kind
385 /// (signed integer / unsigned integer / floating-point)
386 /// with at least the indicated number of bits of precision.
387 template ResizeNumericType(T, uint bits)
388 {
389 static if (is(T : ulong))
390 static if (isSigned!T)
391 alias ResizeNumericType = SignedBitsType!bits;
392 else
393 alias ResizeNumericType = UnsignedBitsType!bits;
394 else
395 static if (is(T : real))
396 {
397 static if (bits <= float.mant_dig)
398 alias ResizeNumericType = float;
399 else
400 static if (bits <= double.mant_dig)
401 alias ResizeNumericType = double;
402 else
403 static if (bits <= real.mant_dig)
404 alias ResizeNumericType = real;
405 else
406 static assert(0, "No floating-point type big enough to fit " ~ bits.stringof ~ " bits");
407 }
408 else
409 static assert(false, "Don't know how to resize type: " ~ T.stringof);
410 }
411
412 static assert(is(ResizeNumericType!(float, double.mant_dig) == double));
413
414 /// Expand to a built-in numeric type of the same kind
415 /// (signed integer / unsigned integer / floating-point)
416 /// with at least additionalBits more bits of precision.
417 alias ExpandNumericType(T, uint additionalBits) =
418 ResizeNumericType!(T, valueBits!T + additionalBits);
419
420 /// Unsigned integer type big enough to fit N bits of precision.
421 template UnsignedBitsType(uint bits)
422 {
423 static if (bits <= 8)
424 alias ubyte UnsignedBitsType;
425 else
426 static if (bits <= 16)
427 alias ushort UnsignedBitsType;
428 else
429 static if (bits <= 32)
430 alias uint UnsignedBitsType;
431 else
432 static if (bits <= 64)
433 alias ulong UnsignedBitsType;
434 else
435 static assert(0, "No integer type big enough to fit " ~ bits.stringof ~ " bits");
436 }
437
438 template SignedBitsType(uint bits)
439 {
440 alias Signed!(UnsignedBitsType!bits) SignedBitsType;
441 }
442
443
444 /// Wrapper around ExpandNumericType to only expand numeric types.
445 template ExpandIntegerType(T, size_t bits)
446 {
447 static if (is(T:real))
448 alias ExpandIntegerType = T;
449 else
450 alias ExpandIntegerType = ExpandNumericType!(T, bits);
451 }
452
453 RGBA blendColor(RGBA fg, RGBA bg, ubyte alpha) pure nothrow @nogc
454 {
455 ubyte invAlpha = cast(ubyte)(~cast(int)alpha);
456 version(LDC)
457 {
458 __m128i alphaMask = _mm_set1_epi32( (invAlpha << 16) | alpha ); // [ alpha invAlpha... (4x)]
459 __m128i mmfg = _mm_cvtsi32_si128( *cast(int*)(&fg) );
460 __m128i mmbg = _mm_cvtsi32_si128( *cast(int*)(&bg) );
461 __m128i zero = _mm_setzero_si128();
462 __m128i colorMask = _mm_unpacklo_epi8(mmfg, mmbg); // [fg.r bg.r fg.g bg.g fg.b bg.b fg.a bg.a 0 (8x) ]
463 colorMask = _mm_unpacklo_epi8(colorMask, zero); // [fg.r bg.r fg.g bg.g fg.b bg.b fg.a bg.a ]
464 __m128i product = _mm_madd_epi16(colorMask, alphaMask); // [ fg[i]*alpha+bg[i]*invAlpha (4x) ]
465
466 // To divide a ushort by 255, LLVM suggests to
467 // * sign multiply by 32897
468 // * right-shift logically by 23
469 // Thanks https://godbolt.org/
470 product *= _mm_set1_epi32(32897); // PERF: this leads to inefficient code with several pmul
471 product = _mm_srli_epi32(product, 23);
472 __m128i c = _mm_packs_epi32(product, zero);
473 c = _mm_packus_epi16(c, zero);
474 RGBA result = void;
475 *cast(int*)(&result) = c[0];
476 return result;
477 }
478 else
479 {
480 // PERF should be a lot to optimize there
481
482 RGBA c = void;
483 c.r = cast(ubyte) ( ( (fg.r * alpha) + (bg.r * invAlpha) ) / ubyte.max );
484 c.g = cast(ubyte) ( ( (fg.g * alpha) + (bg.g * invAlpha) ) / ubyte.max );
485 c.b = cast(ubyte) ( ( (fg.b * alpha) + (bg.b * invAlpha) ) / ubyte.max );
486 c.a = cast(ubyte) ( ( (fg.a * alpha) + (bg.a * invAlpha) ) / ubyte.max );
487 return c;
488 }
489 }
490
491 /// Blend two colors, where `fg` is a premultiplied color by its own alpha.
492 /// We consider fg to be already scaled by (alpha/255)
493 /// Return: (255-alpha)
494 RGBA blendColorPremul(RGBA fg, RGBA bg, ubyte alpha) pure nothrow @nogc
495 {
496 ubyte invAlpha = cast(ubyte)(~cast(int)alpha);
497 RGBA c = void;
498 c.r = cast(ubyte) ( fg.r + (bg.r * invAlpha) / 255 );
499 c.g = cast(ubyte) ( fg.g + (bg.g * invAlpha) / 255 ); // Note: curious lack of rounding
500 c.b = cast(ubyte) ( fg.b + (bg.b * invAlpha) / 255 );
501 c.a = cast(ubyte) ( fg.a + (bg.a * invAlpha) / 255 );
502 return c;
503 }
504
505 RGB blendColor(RGB fg, RGB bg, ubyte alpha) pure nothrow @nogc
506 {
507 ubyte invAlpha = cast(ubyte)(~cast(int)alpha);
508 RGB c = void;
509 c.r = cast(ubyte) ( ( (fg.r * alpha) + (bg.r * invAlpha) ) / ubyte.max );
510 c.g = cast(ubyte) ( ( (fg.g * alpha) + (bg.g * invAlpha) ) / ubyte.max );
511 c.b = cast(ubyte) ( ( (fg.b * alpha) + (bg.b * invAlpha) ) / ubyte.max );
512 return c;
513 }
514
515 L16 blendColor(L16 fg, L16 bg, ushort alpha) pure nothrow @nogc
516 {
517 ushort v = cast(ushort) ( ((fg.l * alpha) + (bg.l * cast(ushort)(~cast(int)alpha))) / ushort.max );
518 return L16(v);
519 }
520
521