1
2/*
3 * Copyright 2006 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#include "SkCoreBlitters.h"
11#include "SkColorPriv.h"
12#include "SkDither.h"
13#include "SkShader.h"
14#include "SkTemplatesPriv.h"
15#include "SkUtils.h"
16#include "SkXfermode.h"
17
18static inline SkPMColor SkBlendARGB4444(SkPMColor16 src, SkPMColor16 dst,
19                                        U8CPU aa) {
20    SkASSERT((unsigned)aa <= 255);
21
22    unsigned src_scale = SkAlpha255To256(aa) >> 4;
23    unsigned dst_scale = SkAlpha15To16(15 - SkAlphaMul4(SkGetPackedA4444(src), src_scale));
24
25    uint32_t src32 = SkExpand_4444(src) * src_scale;
26    uint32_t dst32 = SkExpand_4444(dst) * dst_scale;
27    return SkCompact_4444((src32 + dst32) >> 4);
28}
29
30///////////////////////////////////////////////////////////////////////////////
31
32class SkARGB4444_Blitter : public SkRasterBlitter {
33public:
34    SkARGB4444_Blitter(const SkBitmap& device, const SkPaint& paint);
35    virtual void blitH(int x, int y, int width);
36    virtual void blitAntiH(int x, int y, const SkAlpha antialias[],
37                           const int16_t runs[]);
38    virtual void blitV(int x, int y, int height, SkAlpha alpha);
39    virtual void blitRect(int x, int y, int width, int height);
40    virtual void blitMask(const SkMask&, const SkIRect&);
41    virtual const SkBitmap* justAnOpaqueColor(uint32_t*);
42
43protected:
44    SkPMColor16 fPMColor16, fPMColor16Other;
45    SkPMColor16 fRawColor16, fRawColor16Other;
46    uint8_t     fScale16;
47
48private:
49    // illegal
50    SkARGB4444_Blitter& operator=(const SkARGB4444_Blitter&);
51
52    typedef SkRasterBlitter INHERITED;
53};
54
55
56SkARGB4444_Blitter::SkARGB4444_Blitter(const SkBitmap& device,
57                                   const SkPaint& paint) : INHERITED(device) {
58    // cache premultiplied versions in 4444
59    SkPMColor c = SkPreMultiplyColor(paint.getColor());
60    fPMColor16 = SkPixel32ToPixel4444(c);
61    if (paint.isDither()) {
62        fPMColor16Other = SkDitherPixel32To4444(c);
63    } else {
64        fPMColor16Other = fPMColor16;
65    }
66
67    // cache raw versions in 4444
68    fRawColor16 = SkPackARGB4444(0xFF >> 4, SkColorGetR(c) >> 4,
69                                 SkColorGetG(c) >> 4, SkColorGetB(c) >> 4);
70    if (paint.isDither()) {
71        fRawColor16Other = SkDitherARGB32To4444(0xFF, SkColorGetR(c),
72                                                SkColorGetG(c), SkColorGetB(c));
73    } else {
74        fRawColor16Other = fRawColor16;
75    }
76
77    fScale16 = SkAlpha15To16(SkGetPackedA4444(fPMColor16Other));
78    if (16 == fScale16) {
79        // force the original to also be opaque
80        fPMColor16 |= (0xF << SK_A4444_SHIFT);
81    }
82}
83
84const SkBitmap* SkARGB4444_Blitter::justAnOpaqueColor(uint32_t* value) {
85    if (16 == fScale16) {
86        *value = fPMColor16;
87        return &fDevice;
88    }
89    return NULL;
90}
91
92static void src_over_4444(SkPMColor16 dst[], SkPMColor16 color,
93                          SkPMColor16 other, unsigned invScale, int count) {
94    int twice = count >> 1;
95    while (--twice >= 0) {
96        *dst = color + SkAlphaMulQ4(*dst, invScale);
97        dst++;
98        *dst = other + SkAlphaMulQ4(*dst, invScale);
99        dst++;
100    }
101    if (count & 1) {
102        *dst = color + SkAlphaMulQ4(*dst, invScale);
103    }
104}
105
106static inline uint32_t SkExpand_4444_Replicate(SkPMColor16 c) {
107    uint32_t c32 = SkExpand_4444(c);
108    return c32 | (c32 << 4);
109}
110
111static void src_over_4444x(SkPMColor16 dst[], uint32_t color,
112                           uint32_t other, unsigned invScale, int count) {
113    int twice = count >> 1;
114    uint32_t tmp;
115    while (--twice >= 0) {
116        tmp = SkExpand_4444(*dst) * invScale;
117        *dst++ = SkCompact_4444((color + tmp) >> 4);
118        tmp = SkExpand_4444(*dst) * invScale;
119        *dst++ = SkCompact_4444((other + tmp) >> 4);
120    }
121    if (count & 1) {
122        tmp = SkExpand_4444(*dst) * invScale;
123        *dst = SkCompact_4444((color + tmp) >> 4);
124    }
125}
126
127void SkARGB4444_Blitter::blitH(int x, int y, int width) {
128    SkASSERT(x >= 0 && y >= 0 && x + width <= fDevice.width());
129
130    if (0 == fScale16) {
131        return;
132    }
133
134    SkPMColor16* device = fDevice.getAddr16(x, y);
135    SkPMColor16  color = fPMColor16;
136    SkPMColor16  other = fPMColor16Other;
137
138    if ((x ^ y) & 1) {
139        SkTSwap<SkPMColor16>(color, other);
140    }
141
142    if (16 == fScale16) {
143        sk_dither_memset16(device, color, other, width);
144    } else {
145        src_over_4444x(device, SkExpand_4444_Replicate(color),
146                       SkExpand_4444_Replicate(other),
147                       16 - fScale16, width);
148    }
149}
150
151void SkARGB4444_Blitter::blitV(int x, int y, int height, SkAlpha alpha) {
152    if (0 == alpha || 0 == fScale16) {
153        return;
154    }
155
156    SkPMColor16* device = fDevice.getAddr16(x, y);
157    SkPMColor16  color = fPMColor16;
158    SkPMColor16  other = fPMColor16Other;
159    unsigned     rb = fDevice.rowBytes();
160
161    if ((x ^ y) & 1) {
162        SkTSwap<SkPMColor16>(color, other);
163    }
164
165    if (16 == fScale16 && 255 == alpha) {
166        while (--height >= 0) {
167            *device = color;
168            device = (SkPMColor16*)((char*)device + rb);
169            SkTSwap<SkPMColor16>(color, other);
170        }
171    } else {
172        unsigned alphaScale = SkAlpha255To256(alpha);
173        uint32_t c32 = SkExpand_4444(color) * (alphaScale >> 4);
174        // need to normalize the low nibble of each expanded component
175        // so we don't overflow the add with d32
176        c32 = SkCompact_4444(c32 >> 4);
177        unsigned invScale = 16 - SkAlpha15To16(SkGetPackedA4444(c32));
178        // now re-expand and replicate
179        c32 = SkExpand_4444_Replicate(c32);
180
181        while (--height >= 0) {
182            uint32_t d32 = SkExpand_4444(*device) * invScale;
183            *device = SkCompact_4444((c32 + d32) >> 4);
184            device = (SkPMColor16*)((char*)device + rb);
185        }
186    }
187}
188
189void SkARGB4444_Blitter::blitRect(int x, int y, int width, int height) {
190    SkASSERT(x >= 0 && y >= 0 && x + width <= fDevice.width() &&
191             y + height <= fDevice.height());
192
193    if (0 == fScale16) {
194        return;
195    }
196
197    SkPMColor16* device = fDevice.getAddr16(x, y);
198    SkPMColor16  color = fPMColor16;
199    SkPMColor16  other = fPMColor16Other;
200
201    if ((x ^ y) & 1) {
202        SkTSwap<SkPMColor16>(color, other);
203    }
204
205    if (16 == fScale16) {
206        while (--height >= 0) {
207            sk_dither_memset16(device, color, other, width);
208            device = (SkPMColor16*)((char*)device + fDevice.rowBytes());
209            SkTSwap<SkPMColor16>(color, other);
210        }
211    } else {
212        unsigned invScale = 16 - fScale16;
213
214        uint32_t c32 = SkExpand_4444_Replicate(color);
215        uint32_t o32 = SkExpand_4444_Replicate(other);
216        while (--height >= 0) {
217            src_over_4444x(device, c32, o32, invScale, width);
218            device = (SkPMColor16*)((char*)device + fDevice.rowBytes());
219            SkTSwap<uint32_t>(c32, o32);
220        }
221    }
222}
223
224void SkARGB4444_Blitter::blitAntiH(int x, int y, const SkAlpha antialias[],
225                                   const int16_t runs[]) {
226    if (0 == fScale16) {
227        return;
228    }
229
230    SkPMColor16* device = fDevice.getAddr16(x, y);
231    SkPMColor16  color = fPMColor16;
232    SkPMColor16  other = fPMColor16Other;
233
234    if ((x ^ y) & 1) {
235        SkTSwap<SkPMColor16>(color, other);
236    }
237
238    for (;;) {
239        int count = runs[0];
240        SkASSERT(count >= 0);
241        if (count <= 0) {
242            return;
243        }
244
245        unsigned aa = antialias[0];
246        if (aa) {
247            if (0xFF == aa) {
248                if (16 == fScale16) {
249                    sk_dither_memset16(device, color, other, count);
250                } else {
251                    src_over_4444(device, color, other, 16 - fScale16, count);
252                }
253            } else {
254                // todo: respect dithering
255                aa = SkAlpha255To256(aa);   // FIX
256                SkPMColor16 src = SkAlphaMulQ4(color, aa >> 4);
257                unsigned dst_scale = SkAlpha15To16(15 - SkGetPackedA4444(src)); // FIX
258                int n = count;
259                do {
260                    --n;
261                    device[n] = src + SkAlphaMulQ4(device[n], dst_scale);
262                } while (n > 0);
263            }
264        }
265
266        runs += count;
267        antialias += count;
268        device += count;
269
270        if (count & 1) {
271            SkTSwap<SkPMColor16>(color, other);
272        }
273    }
274}
275
276///////////////////////////////////////////////////////////////////////////////
277
278#define solid_8_pixels(mask, dst, color)    \
279    do {                                    \
280        if (mask & 0x80) dst[0] = color;    \
281        if (mask & 0x40) dst[1] = color;    \
282        if (mask & 0x20) dst[2] = color;    \
283        if (mask & 0x10) dst[3] = color;    \
284        if (mask & 0x08) dst[4] = color;    \
285        if (mask & 0x04) dst[5] = color;    \
286        if (mask & 0x02) dst[6] = color;    \
287        if (mask & 0x01) dst[7] = color;    \
288    } while (0)
289
290#define SK_BLITBWMASK_NAME                  SkARGB4444_BlitBW
291#define SK_BLITBWMASK_ARGS                  , SkPMColor16 color
292#define SK_BLITBWMASK_BLIT8(mask, dst)      solid_8_pixels(mask, dst, color)
293#define SK_BLITBWMASK_GETADDR               getAddr16
294#define SK_BLITBWMASK_DEVTYPE               uint16_t
295#include "SkBlitBWMaskTemplate.h"
296
297#define blend_8_pixels(mask, dst, sc, dst_scale)                             \
298    do {                                                                     \
299        if (mask & 0x80) { dst[0] = sc + SkAlphaMulQ4(dst[0], dst_scale); }  \
300        if (mask & 0x40) { dst[1] = sc + SkAlphaMulQ4(dst[1], dst_scale); }  \
301        if (mask & 0x20) { dst[2] = sc + SkAlphaMulQ4(dst[2], dst_scale); }  \
302        if (mask & 0x10) { dst[3] = sc + SkAlphaMulQ4(dst[3], dst_scale); }  \
303        if (mask & 0x08) { dst[4] = sc + SkAlphaMulQ4(dst[4], dst_scale); }  \
304        if (mask & 0x04) { dst[5] = sc + SkAlphaMulQ4(dst[5], dst_scale); }  \
305        if (mask & 0x02) { dst[6] = sc + SkAlphaMulQ4(dst[6], dst_scale); }  \
306        if (mask & 0x01) { dst[7] = sc + SkAlphaMulQ4(dst[7], dst_scale); }  \
307    } while (0)
308
309#define SK_BLITBWMASK_NAME                  SkARGB4444_BlendBW
310#define SK_BLITBWMASK_ARGS                  , uint16_t sc, unsigned dst_scale
311#define SK_BLITBWMASK_BLIT8(mask, dst)      blend_8_pixels(mask, dst, sc, dst_scale)
312#define SK_BLITBWMASK_GETADDR               getAddr16
313#define SK_BLITBWMASK_DEVTYPE               uint16_t
314#include "SkBlitBWMaskTemplate.h"
315
316void SkARGB4444_Blitter::blitMask(const SkMask& mask, const SkIRect& clip) {
317    SkASSERT(mask.fBounds.contains(clip));
318
319    if (0 == fScale16) {
320        return;
321    }
322
323    if (mask.fFormat == SkMask::kBW_Format) {
324        if (16 == fScale16) {
325            SkARGB4444_BlitBW(fDevice, mask, clip, fPMColor16);
326        } else {
327            SkARGB4444_BlendBW(fDevice, mask, clip, fPMColor16, 16 - fScale16);
328        }
329        return;
330    }
331
332    int x = clip.fLeft;
333    int y = clip.fTop;
334    int width = clip.width();
335    int height = clip.height();
336
337    SkPMColor16*    device = fDevice.getAddr16(x, y);
338    const uint8_t*  alpha = mask.getAddr8(x, y);
339    SkPMColor16     srcColor = fPMColor16;
340    unsigned        devRB = fDevice.rowBytes() - (width << 1);
341    unsigned        maskRB = mask.fRowBytes - width;
342
343    do {
344        int w = width;
345        do {
346            unsigned aa = *alpha++;
347            *device = SkBlendARGB4444(srcColor, *device, aa);
348            device += 1;
349        } while (--w != 0);
350        device = (SkPMColor16*)((char*)device + devRB);
351        alpha += maskRB;
352    } while (--height != 0);
353}
354
355///////////////////////////////////////////////////////////////////////////////
356
357class SkARGB4444_Shader_Blitter : public SkShaderBlitter {
358    SkXfermode*     fXfermode;
359    SkBlitRow::Proc fOpaqueProc;
360    SkBlitRow::Proc fAlphaProc;
361    SkPMColor*      fBuffer;
362    uint8_t*        fAAExpand;
363public:
364
365SkARGB4444_Shader_Blitter(const SkBitmap& device, const SkPaint& paint)
366        : INHERITED(device, paint) {
367    const int width = device.width();
368    fBuffer = (SkPMColor*)sk_malloc_throw(width * sizeof(SkPMColor) + width);
369    fAAExpand = (uint8_t*)(fBuffer + width);
370
371    fXfermode = paint.getXfermode();
372    SkSafeRef(fXfermode);
373
374    unsigned flags = 0;
375    if (!(fShader->getFlags() & SkShader::kOpaqueAlpha_Flag)) {
376        flags |= SkBlitRow::kSrcPixelAlpha_Flag;
377    }
378    if (paint.isDither()) {
379        flags |= SkBlitRow::kDither_Flag;
380    }
381    fOpaqueProc = SkBlitRow::Factory(flags, SkBitmap::kARGB_4444_Config);
382    fAlphaProc = SkBlitRow::Factory(flags | SkBlitRow::kGlobalAlpha_Flag,
383                                    SkBitmap::kARGB_4444_Config);
384}
385
386virtual ~SkARGB4444_Shader_Blitter() {
387    SkSafeUnref(fXfermode);
388    sk_free(fBuffer);
389}
390
391virtual void blitH(int x, int y, int width) {
392    SkASSERT(x >= 0 && y >= 0 && x + width <= fDevice.width());
393
394    SkPMColor16* device = fDevice.getAddr16(x, y);
395    SkPMColor*   span = fBuffer;
396
397    fShader->shadeSpan(x, y, span, width);
398    if (fXfermode) {
399        fXfermode->xfer4444(device, span, width, NULL);
400    } else {
401        fOpaqueProc(device, span, width, 0xFF, x, y);
402    }
403}
404
405virtual void blitAntiH(int x, int y, const SkAlpha antialias[],
406                       const int16_t runs[]) {
407    SkPMColor* SK_RESTRICT span = fBuffer;
408    uint8_t* SK_RESTRICT aaExpand = fAAExpand;
409    SkPMColor16* device = fDevice.getAddr16(x, y);
410    SkShader*    shader = fShader;
411    SkXfermode*  xfer = fXfermode;
412
413    if (NULL != xfer) {
414        for (;;) {
415            int count = *runs;
416            if (count <= 0) {
417                break;
418            }
419            int aa = *antialias;
420            if (aa) {
421                shader->shadeSpan(x, y, span, count);
422                if (255 == aa) {
423                    xfer->xfer4444(device, span, count, NULL);
424                } else {
425                    const uint8_t* aaBuffer = antialias;
426                    if (count > 1) {
427                        memset(aaExpand, aa, count);
428                        aaBuffer = aaExpand;
429                    }
430                    xfer->xfer4444(device, span, count, aaBuffer);
431                }
432            }
433            device += count;
434            runs += count;
435            antialias += count;
436            x += count;
437        }
438    } else {    // no xfermode
439        for (;;) {
440            int count = *runs;
441            if (count <= 0) {
442                break;
443            }
444            int aa = *antialias;
445            if (aa) {
446                fShader->shadeSpan(x, y, span, count);
447                if (255 == aa) {
448                    fOpaqueProc(device, span, count, aa, x, y);
449                } else {
450                    fAlphaProc(device, span, count, aa, x, y);
451                }
452            }
453            device += count;
454            runs += count;
455            antialias += count;
456            x += count;
457        }
458    }
459}
460
461private:
462    typedef SkShaderBlitter INHERITED;
463};
464
465///////////////////////////////////////////////////////////////////////////////
466///////////////////////////////////////////////////////////////////////////////
467
468SkBlitter* SkBlitter_ChooseD4444(const SkBitmap& device,
469                                 const SkPaint& paint,
470                                 void* storage, size_t storageSize)
471{
472    SkBlitter* blitter;
473
474    if (paint.getShader()) {
475        SK_PLACEMENT_NEW_ARGS(blitter, SkARGB4444_Shader_Blitter, storage, storageSize, (device, paint));
476    } else {
477        SK_PLACEMENT_NEW_ARGS(blitter, SkARGB4444_Blitter, storage, storageSize, (device, paint));
478    }
479    return blitter;
480}
481
482