| |
| /* |
| * Copyright 2011 The Android Open Source Project |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| |
| #include "SkScan.h" |
| #include "SkBlitter.h" |
| #include "SkColorPriv.h" |
| #include "SkLineClipper.h" |
| #include "SkRasterClip.h" |
| #include "SkFDot6.h" |
| |
| /* Our attempt to compute the worst case "bounds" for the horizontal and |
| vertical cases has some numerical bug in it, and we sometimes undervalue |
| our extends. The bug is that when this happens, we will set the clip to |
| NULL (for speed), and thus draw outside of the clip by a pixel, which might |
| only look bad, but it might also access memory outside of the valid range |
| allcoated for the device bitmap. |
| |
| This define enables our fix to outset our "bounds" by 1, thus avoiding the |
| chance of the bug, but at the cost of sometimes taking the rectblitter |
| case (i.e. not setting the clip to NULL) when we might not actually need |
| to. If we can improve/fix the actual calculations, then we can remove this |
| step. |
| */ |
| #define OUTSET_BEFORE_CLIP_TEST true |
| |
| #define HLINE_STACK_BUFFER 100 |
| |
| static inline int SmallDot6Scale(int value, int dot6) { |
| SkASSERT((int16_t)value == value); |
| SkASSERT((unsigned)dot6 <= 64); |
| return SkMulS16(value, dot6) >> 6; |
| } |
| |
| //#define TEST_GAMMA |
| |
| #ifdef TEST_GAMMA |
| static uint8_t gGammaTable[256]; |
| #define ApplyGamma(table, alpha) (table)[alpha] |
| |
| static void build_gamma_table() { |
| static bool gInit = false; |
| |
| if (gInit == false) { |
| for (int i = 0; i < 256; i++) { |
| SkFixed n = i * 257; |
| n += n >> 15; |
| SkASSERT(n >= 0 && n <= SK_Fixed1); |
| n = SkFixedSqrt(n); |
| n = n * 255 >> 16; |
| // SkDebugf("morph %d -> %d\n", i, n); |
| gGammaTable[i] = SkToU8(n); |
| } |
| gInit = true; |
| } |
| } |
| #else |
| #define ApplyGamma(table, alpha) SkToU8(alpha) |
| #endif |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| static void call_hline_blitter(SkBlitter* blitter, int x, int y, int count, |
| U8CPU alpha) { |
| SkASSERT(count > 0); |
| |
| int16_t runs[HLINE_STACK_BUFFER + 1]; |
| uint8_t aa[HLINE_STACK_BUFFER]; |
| |
| aa[0] = ApplyGamma(gGammaTable, alpha); |
| do { |
| int n = count; |
| if (n > HLINE_STACK_BUFFER) { |
| n = HLINE_STACK_BUFFER; |
| } |
| runs[0] = SkToS16(n); |
| runs[n] = 0; |
| blitter->blitAntiH(x, y, aa, runs); |
| x += n; |
| count -= n; |
| } while (count > 0); |
| } |
| |
| static SkFixed hline(int x, int stopx, SkFixed fy, SkFixed /*slope*/, |
| SkBlitter* blitter, int mod64) { |
| SkASSERT(x < stopx); |
| int count = stopx - x; |
| fy += SK_Fixed1/2; |
| |
| int y = fy >> 16; |
| uint8_t a = (uint8_t)(fy >> 8); |
| |
| // lower line |
| unsigned ma = SmallDot6Scale(a, mod64); |
| if (ma) { |
| call_hline_blitter(blitter, x, y, count, ma); |
| } |
| |
| // upper line |
| ma = SmallDot6Scale(255 - a, mod64); |
| if (ma) { |
| call_hline_blitter(blitter, x, y - 1, count, ma); |
| } |
| |
| return fy - SK_Fixed1/2; |
| } |
| |
| static SkFixed horish(int x, int stopx, SkFixed fy, SkFixed dy, |
| SkBlitter* blitter, int mod64) { |
| SkASSERT(x < stopx); |
| |
| #ifdef TEST_GAMMA |
| const uint8_t* gamma = gGammaTable; |
| #endif |
| int16_t runs[2]; |
| uint8_t aa[1]; |
| |
| runs[0] = 1; |
| runs[1] = 0; |
| |
| fy += SK_Fixed1/2; |
| do { |
| int lower_y = fy >> 16; |
| uint8_t a = (uint8_t)(fy >> 8); |
| unsigned ma = SmallDot6Scale(a, mod64); |
| if (ma) { |
| aa[0] = ApplyGamma(gamma, ma); |
| blitter->blitAntiH(x, lower_y, aa, runs); |
| // the clipping blitters might edit runs, but should not affect us |
| SkASSERT(runs[0] == 1); |
| SkASSERT(runs[1] == 0); |
| } |
| ma = SmallDot6Scale(255 - a, mod64); |
| if (ma) { |
| aa[0] = ApplyGamma(gamma, ma); |
| blitter->blitAntiH(x, lower_y - 1, aa, runs); |
| // the clipping blitters might edit runs, but should not affect us |
| SkASSERT(runs[0] == 1); |
| SkASSERT(runs[1] == 0); |
| } |
| fy += dy; |
| } while (++x < stopx); |
| |
| return fy - SK_Fixed1/2; |
| } |
| |
| static SkFixed vline(int y, int stopy, SkFixed fx, SkFixed /*slope*/, |
| SkBlitter* blitter, int mod64) { |
| SkASSERT(y < stopy); |
| fx += SK_Fixed1/2; |
| |
| int x = fx >> 16; |
| int a = (uint8_t)(fx >> 8); |
| |
| unsigned ma = SmallDot6Scale(a, mod64); |
| if (ma) { |
| blitter->blitV(x, y, stopy - y, ApplyGamma(gGammaTable, ma)); |
| } |
| ma = SmallDot6Scale(255 - a, mod64); |
| if (ma) { |
| blitter->blitV(x - 1, y, stopy - y, ApplyGamma(gGammaTable, ma)); |
| } |
| |
| return fx - SK_Fixed1/2; |
| } |
| |
| static SkFixed vertish(int y, int stopy, SkFixed fx, SkFixed dx, |
| SkBlitter* blitter, int mod64) { |
| SkASSERT(y < stopy); |
| #ifdef TEST_GAMMA |
| const uint8_t* gamma = gGammaTable; |
| #endif |
| int16_t runs[3]; |
| uint8_t aa[2]; |
| |
| runs[0] = 1; |
| runs[2] = 0; |
| |
| fx += SK_Fixed1/2; |
| do { |
| int x = fx >> 16; |
| uint8_t a = (uint8_t)(fx >> 8); |
| |
| aa[0] = ApplyGamma(gamma, SmallDot6Scale(255 - a, mod64)); |
| aa[1] = ApplyGamma(gamma, SmallDot6Scale(a, mod64)); |
| // the clippng blitters might overwrite this guy, so we have to reset it each time |
| runs[1] = 1; |
| blitter->blitAntiH(x - 1, y, aa, runs); |
| // the clipping blitters might edit runs, but should not affect us |
| SkASSERT(runs[0] == 1); |
| SkASSERT(runs[2] == 0); |
| fx += dx; |
| } while (++y < stopy); |
| |
| return fx - SK_Fixed1/2; |
| } |
| |
| typedef SkFixed (*LineProc)(int istart, int istop, SkFixed fstart, |
| SkFixed slope, SkBlitter*, int); |
| |
| static inline SkFixed fastfixdiv(SkFDot6 a, SkFDot6 b) { |
| SkASSERT((a << 16 >> 16) == a); |
| SkASSERT(b != 0); |
| return (a << 16) / b; |
| } |
| |
| static void do_anti_hairline(SkFDot6 x0, SkFDot6 y0, SkFDot6 x1, SkFDot6 y1, |
| const SkIRect* clip, SkBlitter* blitter) { |
| // check that we're no larger than 511 pixels (so we can do a faster div). |
| // if we are, subdivide and call again |
| |
| if (SkAbs32(x1 - x0) > SkIntToFDot6(511) || SkAbs32(y1 - y0) > SkIntToFDot6(511)) { |
| /* instead of (x0 + x1) >> 1, we shift each separately. This is less |
| precise, but avoids overflowing the intermediate result if the |
| values are huge. A better fix might be to clip the original pts |
| directly (i.e. do the divide), so we don't spend time subdividing |
| huge lines at all. |
| */ |
| int hx = (x0 >> 1) + (x1 >> 1); |
| int hy = (y0 >> 1) + (y1 >> 1); |
| do_anti_hairline(x0, y0, hx, hy, clip, blitter); |
| do_anti_hairline(hx, hy, x1, y1, clip, blitter); |
| return; |
| } |
| |
| int scaleStart, scaleStop; |
| int istart, istop; |
| SkFixed fstart, slope; |
| LineProc proc; |
| |
| if (SkAbs32(x1 - x0) > SkAbs32(y1 - y0)) { // mostly horizontal |
| if (x0 > x1) { // we want to go left-to-right |
| SkTSwap<SkFDot6>(x0, x1); |
| SkTSwap<SkFDot6>(y0, y1); |
| } |
| |
| istart = SkFDot6Floor(x0); |
| istop = SkFDot6Ceil(x1); |
| fstart = SkFDot6ToFixed(y0); |
| if (y0 == y1) { // completely horizontal, take fast case |
| slope = 0; |
| proc = hline; |
| } else { |
| slope = fastfixdiv(y1 - y0, x1 - x0); |
| SkASSERT(slope >= -SK_Fixed1 && slope <= SK_Fixed1); |
| fstart += (slope * (32 - (x0 & 63)) + 32) >> 6; |
| proc = horish; |
| } |
| |
| SkASSERT(istop > istart); |
| if (istop - istart == 1) { |
| scaleStart = x1 - x0; |
| SkASSERT(scaleStart >= 0 && scaleStart <= 64); |
| scaleStop = 0; |
| } else { |
| scaleStart = 64 - (x0 & 63); |
| scaleStop = x1 & 63; |
| } |
| |
| if (clip){ |
| if (istart >= clip->fRight || istop <= clip->fLeft) { |
| return; |
| } |
| if (istart < clip->fLeft) { |
| fstart += slope * (clip->fLeft - istart); |
| istart = clip->fLeft; |
| scaleStart = 64; |
| } |
| if (istop > clip->fRight) { |
| istop = clip->fRight; |
| scaleStop = 64; |
| } |
| SkASSERT(istart <= istop); |
| if (istart == istop) { |
| return; |
| } |
| // now test if our Y values are completely inside the clip |
| int top, bottom; |
| if (slope >= 0) { // T2B |
| top = SkFixedFloor(fstart - SK_FixedHalf); |
| bottom = SkFixedCeil(fstart + (istop - istart - 1) * slope + SK_FixedHalf); |
| } else { // B2T |
| bottom = SkFixedCeil(fstart + SK_FixedHalf); |
| top = SkFixedFloor(fstart + (istop - istart - 1) * slope - SK_FixedHalf); |
| } |
| #ifdef OUTSET_BEFORE_CLIP_TEST |
| top -= 1; |
| bottom += 1; |
| #endif |
| if (top >= clip->fBottom || bottom <= clip->fTop) { |
| return; |
| } |
| if (clip->fTop <= top && clip->fBottom >= bottom) { |
| clip = NULL; |
| } |
| } |
| } else { // mostly vertical |
| if (y0 > y1) { // we want to go top-to-bottom |
| SkTSwap<SkFDot6>(x0, x1); |
| SkTSwap<SkFDot6>(y0, y1); |
| } |
| |
| istart = SkFDot6Floor(y0); |
| istop = SkFDot6Ceil(y1); |
| fstart = SkFDot6ToFixed(x0); |
| if (x0 == x1) { |
| if (y0 == y1) { // are we zero length? |
| return; // nothing to do |
| } |
| slope = 0; |
| proc = vline; |
| } else { |
| slope = fastfixdiv(x1 - x0, y1 - y0); |
| SkASSERT(slope <= SK_Fixed1 && slope >= -SK_Fixed1); |
| fstart += (slope * (32 - (y0 & 63)) + 32) >> 6; |
| proc = vertish; |
| } |
| |
| SkASSERT(istop > istart); |
| if (istop - istart == 1) { |
| scaleStart = y1 - y0; |
| SkASSERT(scaleStart >= 0 && scaleStart <= 64); |
| scaleStop = 0; |
| } else { |
| scaleStart = 64 - (y0 & 63); |
| scaleStop = y1 & 63; |
| } |
| |
| if (clip) { |
| if (istart >= clip->fBottom || istop <= clip->fTop) { |
| return; |
| } |
| if (istart < clip->fTop) { |
| fstart += slope * (clip->fTop - istart); |
| istart = clip->fTop; |
| scaleStart = 64; |
| } |
| if (istop > clip->fBottom) { |
| istop = clip->fBottom; |
| scaleStop = 64; |
| } |
| SkASSERT(istart <= istop); |
| if (istart == istop) |
| return; |
| |
| // now test if our X values are completely inside the clip |
| int left, right; |
| if (slope >= 0) { // L2R |
| left = SkFixedFloor(fstart - SK_FixedHalf); |
| right = SkFixedCeil(fstart + (istop - istart - 1) * slope + SK_FixedHalf); |
| } else { // R2L |
| right = SkFixedCeil(fstart + SK_FixedHalf); |
| left = SkFixedFloor(fstart + (istop - istart - 1) * slope - SK_FixedHalf); |
| } |
| #ifdef OUTSET_BEFORE_CLIP_TEST |
| left -= 1; |
| right += 1; |
| #endif |
| if (left >= clip->fRight || right <= clip->fLeft) { |
| return; |
| } |
| if (clip->fLeft <= left && clip->fRight >= right) { |
| clip = NULL; |
| } |
| } |
| } |
| |
| SkRectClipBlitter rectClipper; |
| if (clip) { |
| rectClipper.init(blitter, *clip); |
| blitter = &rectClipper; |
| } |
| |
| fstart = proc(istart, istart + 1, fstart, slope, blitter, scaleStart); |
| istart += 1; |
| int fullSpans = istop - istart - (scaleStop > 0); |
| if (fullSpans > 0) { |
| fstart = proc(istart, istart + fullSpans, fstart, slope, blitter, 64); |
| } |
| if (scaleStop > 0) { |
| proc(istop - 1, istop, fstart, slope, blitter, scaleStop); |
| } |
| } |
| |
| void SkScan::AntiHairLineRgn(const SkPoint& pt0, const SkPoint& pt1, |
| const SkRegion* clip, SkBlitter* blitter) { |
| if (clip && clip->isEmpty()) { |
| return; |
| } |
| |
| SkASSERT(clip == NULL || !clip->getBounds().isEmpty()); |
| |
| #ifdef TEST_GAMMA |
| build_gamma_table(); |
| #endif |
| |
| SkPoint pts[2] = { pt0, pt1 }; |
| |
| if (clip) { |
| SkRect clipBounds; |
| clipBounds.set(clip->getBounds()); |
| /* We perform integral clipping later on, but we do a scalar clip first |
| to ensure that our coordinates are expressible in fixed/integers. |
| |
| antialiased hairlines can draw up to 1/2 of a pixel outside of |
| their bounds, so we need to outset the clip before calling the |
| clipper. To make the numerics safer, we outset by a whole pixel, |
| since the 1/2 pixel boundary is important to the antihair blitter, |
| we don't want to risk numerical fate by chopping on that edge. |
| */ |
| clipBounds.inset(-SK_Scalar1, -SK_Scalar1); |
| |
| if (!SkLineClipper::IntersectLine(pts, clipBounds, pts)) { |
| return; |
| } |
| } |
| |
| SkFDot6 x0 = SkScalarToFDot6(pts[0].fX); |
| SkFDot6 y0 = SkScalarToFDot6(pts[0].fY); |
| SkFDot6 x1 = SkScalarToFDot6(pts[1].fX); |
| SkFDot6 y1 = SkScalarToFDot6(pts[1].fY); |
| |
| if (clip) { |
| SkFDot6 left = SkMin32(x0, x1); |
| SkFDot6 top = SkMin32(y0, y1); |
| SkFDot6 right = SkMax32(x0, x1); |
| SkFDot6 bottom = SkMax32(y0, y1); |
| SkIRect ir; |
| |
| ir.set( SkFDot6Floor(left) - 1, |
| SkFDot6Floor(top) - 1, |
| SkFDot6Ceil(right) + 1, |
| SkFDot6Ceil(bottom) + 1); |
| |
| if (clip->quickReject(ir)) { |
| return; |
| } |
| if (!clip->quickContains(ir)) { |
| SkRegion::Cliperator iter(*clip, ir); |
| const SkIRect* r = &iter.rect(); |
| |
| while (!iter.done()) { |
| do_anti_hairline(x0, y0, x1, y1, r, blitter); |
| iter.next(); |
| } |
| return; |
| } |
| // fall through to no-clip case |
| } |
| do_anti_hairline(x0, y0, x1, y1, NULL, blitter); |
| } |
| |
| void SkScan::AntiHairRect(const SkRect& rect, const SkRasterClip& clip, |
| SkBlitter* blitter) { |
| SkPoint p0, p1; |
| |
| p0.set(rect.fLeft, rect.fTop); |
| p1.set(rect.fRight, rect.fTop); |
| SkScan::AntiHairLine(p0, p1, clip, blitter); |
| p0.set(rect.fRight, rect.fBottom); |
| SkScan::AntiHairLine(p0, p1, clip, blitter); |
| p1.set(rect.fLeft, rect.fBottom); |
| SkScan::AntiHairLine(p0, p1, clip, blitter); |
| p0.set(rect.fLeft, rect.fTop); |
| SkScan::AntiHairLine(p0, p1, clip, blitter); |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| typedef int FDot8; // 24.8 integer fixed point |
| |
| static inline FDot8 SkFixedToFDot8(SkFixed x) { |
| return (x + 0x80) >> 8; |
| } |
| |
| static void do_scanline(FDot8 L, int top, FDot8 R, U8CPU alpha, |
| SkBlitter* blitter) { |
| SkASSERT(L < R); |
| |
| if ((L >> 8) == ((R - 1) >> 8)) { // 1x1 pixel |
| blitter->blitV(L >> 8, top, 1, SkAlphaMul(alpha, R - L)); |
| return; |
| } |
| |
| int left = L >> 8; |
| |
| if (L & 0xFF) { |
| blitter->blitV(left, top, 1, SkAlphaMul(alpha, 256 - (L & 0xFF))); |
| left += 1; |
| } |
| |
| int rite = R >> 8; |
| int width = rite - left; |
| if (width > 0) { |
| call_hline_blitter(blitter, left, top, width, alpha); |
| } |
| if (R & 0xFF) { |
| blitter->blitV(rite, top, 1, SkAlphaMul(alpha, R & 0xFF)); |
| } |
| } |
| |
| static void antifilldot8(FDot8 L, FDot8 T, FDot8 R, FDot8 B, SkBlitter* blitter, |
| bool fillInner) { |
| // check for empty now that we're in our reduced precision space |
| if (L >= R || T >= B) { |
| return; |
| } |
| int top = T >> 8; |
| if (top == ((B - 1) >> 8)) { // just one scanline high |
| do_scanline(L, top, R, B - T - 1, blitter); |
| return; |
| } |
| |
| if (T & 0xFF) { |
| do_scanline(L, top, R, 256 - (T & 0xFF), blitter); |
| top += 1; |
| } |
| |
| int bot = B >> 8; |
| int height = bot - top; |
| if (height > 0) { |
| int left = L >> 8; |
| if (left == ((R - 1) >> 8)) { // just 1-pixel wide |
| blitter->blitV(left, top, height, R - L - 1); |
| } else { |
| if (L & 0xFF) { |
| blitter->blitV(left, top, height, 256 - (L & 0xFF)); |
| left += 1; |
| } |
| int rite = R >> 8; |
| int width = rite - left; |
| if (width > 0 && fillInner) { |
| blitter->blitRect(left, top, width, height); |
| } |
| if (R & 0xFF) { |
| blitter->blitV(rite, top, height, R & 0xFF); |
| } |
| } |
| } |
| |
| if (B & 0xFF) { |
| do_scanline(L, bot, R, B & 0xFF, blitter); |
| } |
| } |
| |
| static void antifillrect(const SkXRect& xr, SkBlitter* blitter) { |
| antifilldot8(SkFixedToFDot8(xr.fLeft), SkFixedToFDot8(xr.fTop), |
| SkFixedToFDot8(xr.fRight), SkFixedToFDot8(xr.fBottom), |
| blitter, true); |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| void SkScan::AntiFillXRect(const SkXRect& xr, const SkRegion* clip, |
| SkBlitter* blitter) { |
| if (NULL == clip) { |
| antifillrect(xr, blitter); |
| } else { |
| SkIRect outerBounds; |
| XRect_roundOut(xr, &outerBounds); |
| |
| if (clip->isRect()) { |
| const SkIRect& clipBounds = clip->getBounds(); |
| |
| if (clipBounds.contains(outerBounds)) { |
| antifillrect(xr, blitter); |
| } else { |
| SkXRect tmpR; |
| // this keeps our original edges fractional |
| XRect_set(&tmpR, clipBounds); |
| if (tmpR.intersect(xr)) { |
| antifillrect(tmpR, blitter); |
| } |
| } |
| } else { |
| SkRegion::Cliperator clipper(*clip, outerBounds); |
| const SkIRect& rr = clipper.rect(); |
| |
| while (!clipper.done()) { |
| SkXRect tmpR; |
| |
| // this keeps our original edges fractional |
| XRect_set(&tmpR, rr); |
| if (tmpR.intersect(xr)) { |
| antifillrect(tmpR, blitter); |
| } |
| clipper.next(); |
| } |
| } |
| } |
| } |
| |
| void SkScan::AntiFillXRect(const SkXRect& xr, const SkRasterClip& clip, |
| SkBlitter* blitter) { |
| if (clip.isBW()) { |
| AntiFillXRect(xr, &clip.bwRgn(), blitter); |
| } else { |
| SkIRect outerBounds; |
| XRect_roundOut(xr, &outerBounds); |
| |
| if (clip.quickContains(outerBounds)) { |
| AntiFillXRect(xr, NULL, blitter); |
| } else { |
| SkAAClipBlitterWrapper wrapper(clip, blitter); |
| blitter = wrapper.getBlitter(); |
| |
| AntiFillXRect(xr, &wrapper.getRgn(), wrapper.getBlitter()); |
| } |
| } |
| } |
| |
| #ifdef SK_SCALAR_IS_FLOAT |
| |
| /* This guy takes a float-rect, but with the key improvement that it has |
| already been clipped, so we know that it is safe to convert it into a |
| XRect (fixedpoint), as it won't overflow. |
| */ |
| static void antifillrect(const SkRect& r, SkBlitter* blitter) { |
| SkXRect xr; |
| |
| XRect_set(&xr, r); |
| antifillrect(xr, blitter); |
| } |
| |
| /* We repeat the clipping logic of AntiFillXRect because the float rect might |
| overflow if we blindly converted it to an XRect. This sucks that we have to |
| repeat the clipping logic, but I don't see how to share the code/logic. |
| |
| We clip r (as needed) into one or more (smaller) float rects, and then pass |
| those to our version of antifillrect, which converts it into an XRect and |
| then calls the blit. |
| */ |
| void SkScan::AntiFillRect(const SkRect& origR, const SkRegion* clip, |
| SkBlitter* blitter) { |
| if (clip) { |
| SkRect newR; |
| newR.set(clip->getBounds()); |
| if (!newR.intersect(origR)) { |
| return; |
| } |
| |
| SkIRect outerBounds; |
| newR.roundOut(&outerBounds); |
| |
| if (clip->isRect()) { |
| antifillrect(newR, blitter); |
| } else { |
| SkRegion::Cliperator clipper(*clip, outerBounds); |
| while (!clipper.done()) { |
| newR.set(clipper.rect()); |
| if (newR.intersect(origR)) { |
| antifillrect(newR, blitter); |
| } |
| clipper.next(); |
| } |
| } |
| } else { |
| antifillrect(origR, blitter); |
| } |
| } |
| |
| void SkScan::AntiFillRect(const SkRect& r, const SkRasterClip& clip, |
| SkBlitter* blitter) { |
| if (clip.isBW()) { |
| AntiFillRect(r, &clip.bwRgn(), blitter); |
| } else { |
| SkAAClipBlitterWrapper wrap(clip, blitter); |
| AntiFillRect(r, &wrap.getRgn(), wrap.getBlitter()); |
| } |
| } |
| |
| #endif // SK_SCALAR_IS_FLOAT |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #define SkAlphaMulRound(a, b) SkMulDiv255Round(a, b) |
| |
| // calls blitRect() if the rectangle is non-empty |
| static void fillcheckrect(int L, int T, int R, int B, SkBlitter* blitter) { |
| if (L < R && T < B) { |
| blitter->blitRect(L, T, R - L, B - T); |
| } |
| } |
| |
| static inline FDot8 SkScalarToFDot8(SkScalar x) { |
| #ifdef SK_SCALAR_IS_FLOAT |
| return (int)(x * 256); |
| #else |
| return x >> 8; |
| #endif |
| } |
| |
| static inline int FDot8Floor(FDot8 x) { |
| return x >> 8; |
| } |
| |
| static inline int FDot8Ceil(FDot8 x) { |
| return (x + 0xFF) >> 8; |
| } |
| |
| // 1 - (1 - a)*(1 - b) |
| static inline U8CPU InvAlphaMul(U8CPU a, U8CPU b) { |
| // need precise rounding (not just SkAlphaMul) so that values like |
| // a=228, b=252 don't overflow the result |
| return SkToU8(a + b - SkAlphaMulRound(a, b)); |
| } |
| |
| static void inner_scanline(FDot8 L, int top, FDot8 R, U8CPU alpha, |
| SkBlitter* blitter) { |
| SkASSERT(L < R); |
| |
| if ((L >> 8) == ((R - 1) >> 8)) { // 1x1 pixel |
| blitter->blitV(L >> 8, top, 1, InvAlphaMul(alpha, R - L)); |
| return; |
| } |
| |
| int left = L >> 8; |
| if (L & 0xFF) { |
| blitter->blitV(left, top, 1, InvAlphaMul(alpha, L & 0xFF)); |
| left += 1; |
| } |
| |
| int rite = R >> 8; |
| int width = rite - left; |
| if (width > 0) { |
| call_hline_blitter(blitter, left, top, width, alpha); |
| } |
| |
| if (R & 0xFF) { |
| blitter->blitV(rite, top, 1, InvAlphaMul(alpha, ~R & 0xFF)); |
| } |
| } |
| |
| static void innerstrokedot8(FDot8 L, FDot8 T, FDot8 R, FDot8 B, |
| SkBlitter* blitter) { |
| SkASSERT(L < R && T < B); |
| |
| int top = T >> 8; |
| if (top == ((B - 1) >> 8)) { // just one scanline high |
| inner_scanline(L, top, R, B - T, blitter); |
| return; |
| } |
| |
| if (T & 0xFF) { |
| inner_scanline(L, top, R, T & 0xFF, blitter); |
| top += 1; |
| } |
| |
| int bot = B >> 8; |
| int height = bot - top; |
| if (height > 0) { |
| if (L & 0xFF) { |
| blitter->blitV(L >> 8, top, height, L & 0xFF); |
| } |
| if (R & 0xFF) { |
| blitter->blitV(R >> 8, top, height, ~R & 0xFF); |
| } |
| } |
| |
| if (B & 0xFF) { |
| inner_scanline(L, bot, R, ~B & 0xFF, blitter); |
| } |
| } |
| |
| void SkScan::AntiFrameRect(const SkRect& r, const SkPoint& strokeSize, |
| const SkRegion* clip, SkBlitter* blitter) { |
| SkASSERT(strokeSize.fX >= 0 && strokeSize.fY >= 0); |
| |
| SkScalar rx = SkScalarHalf(strokeSize.fX); |
| SkScalar ry = SkScalarHalf(strokeSize.fY); |
| |
| // outset by the radius |
| FDot8 L = SkScalarToFDot8(r.fLeft - rx); |
| FDot8 T = SkScalarToFDot8(r.fTop - ry); |
| FDot8 R = SkScalarToFDot8(r.fRight + rx); |
| FDot8 B = SkScalarToFDot8(r.fBottom + ry); |
| |
| SkIRect outer; |
| // set outer to the outer rect of the outer section |
| outer.set(FDot8Floor(L), FDot8Floor(T), FDot8Ceil(R), FDot8Ceil(B)); |
| |
| SkBlitterClipper clipper; |
| if (clip) { |
| if (clip->quickReject(outer)) { |
| return; |
| } |
| if (!clip->contains(outer)) { |
| blitter = clipper.apply(blitter, clip, &outer); |
| } |
| // now we can ignore clip for the rest of the function |
| } |
| |
| // stroke the outer hull |
| antifilldot8(L, T, R, B, blitter, false); |
| |
| // set outer to the outer rect of the middle section |
| outer.set(FDot8Ceil(L), FDot8Ceil(T), FDot8Floor(R), FDot8Floor(B)); |
| |
| // in case we lost a bit with diameter/2 |
| rx = strokeSize.fX - rx; |
| ry = strokeSize.fY - ry; |
| // inset by the radius |
| L = SkScalarToFDot8(r.fLeft + rx); |
| T = SkScalarToFDot8(r.fTop + ry); |
| R = SkScalarToFDot8(r.fRight - rx); |
| B = SkScalarToFDot8(r.fBottom - ry); |
| |
| if (L >= R || T >= B) { |
| fillcheckrect(outer.fLeft, outer.fTop, outer.fRight, outer.fBottom, |
| blitter); |
| } else { |
| SkIRect inner; |
| // set inner to the inner rect of the middle section |
| inner.set(FDot8Floor(L), FDot8Floor(T), FDot8Ceil(R), FDot8Ceil(B)); |
| |
| // draw the frame in 4 pieces |
| fillcheckrect(outer.fLeft, outer.fTop, outer.fRight, inner.fTop, |
| blitter); |
| fillcheckrect(outer.fLeft, inner.fTop, inner.fLeft, inner.fBottom, |
| blitter); |
| fillcheckrect(inner.fRight, inner.fTop, outer.fRight, inner.fBottom, |
| blitter); |
| fillcheckrect(outer.fLeft, inner.fBottom, outer.fRight, outer.fBottom, |
| blitter); |
| |
| // now stroke the inner rect, which is similar to antifilldot8() except that |
| // it treats the fractional coordinates with the inverse bias (since its |
| // inner). |
| innerstrokedot8(L, T, R, B, blitter); |
| } |
| } |
| |
| void SkScan::AntiFrameRect(const SkRect& r, const SkPoint& strokeSize, |
| const SkRasterClip& clip, SkBlitter* blitter) { |
| if (clip.isBW()) { |
| AntiFrameRect(r, strokeSize, &clip.bwRgn(), blitter); |
| } else { |
| SkAAClipBlitterWrapper wrap(clip, blitter); |
| AntiFrameRect(r, strokeSize, &wrap.getRgn(), wrap.getBlitter()); |
| } |
| } |
| |
