| /* |
| * Copyright 2022 Google LLC |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "include/core/SkCanvas.h" |
| #include "include/core/SkM44.h" |
| #include "include/core/SkPaint.h" |
| #include "include/core/SkRRect.h" |
| #include "include/core/SkVertices.h" |
| #include "include/private/base/SkTPin.h" |
| #include "tools/viewer/ClickHandlerSlide.h" |
| |
| #include <unordered_set> |
| |
| static SkPaint paint(SkColor color, |
| float strokeWidth = -1.f, |
| SkPaint::Join join = SkPaint::kMiter_Join) { |
| SkPaint paint; |
| paint.setColor(color); |
| paint.setAntiAlias(true); |
| if (strokeWidth >= 0.f) { |
| paint.setStyle(SkPaint::kStroke_Style); |
| paint.setStrokeWidth(strokeWidth); |
| paint.setStrokeJoin(join); |
| } |
| return paint; |
| } |
| |
| // Singular values for [a b][c d] 2x2 matrix, unordered. |
| static std::pair<float, float> singular_values(float a, float b, float c, float d) { |
| float s1 = a*a + b*b + c*c + d*d; |
| |
| float e = a*a + b*b - c*c - d*d; |
| float f = a*c + b*d; |
| float s2 = SkScalarSqrt(e*e + 4*f*f); |
| |
| float singular1 = SkScalarSqrt(0.5f * (s1 + s2)); |
| float singular2 = SkScalarSqrt(0.5f * (s1 - s2)); |
| |
| return {singular1, singular2}; |
| } |
| |
| static constexpr float kAARadius = 10.f; |
| |
| // [m00 m01 * m03] [f(u,v)] |
| // Assuming M = [m10 m11 * m13], define the projected p'(u,v) = [g(u,v)] where |
| // [ * * * * ] |
| // [m30 m31 * m33] |
| // [x] [u] |
| // f(u,v) = x(u,v) / w(u,v), g(u,v) = y(u,v) / w(u,v) and [y] = M*[v] |
| // [*] = [0] |
| // [w] [1] |
| // |
| // x(u,v) = m00*u + m01*v + m03 |
| // y(u,v) = m10*u + m11*v + m13 |
| // w(u,v) = m30*u + m31*v + m33 |
| // |
| // dx/du = m00, dx/dv = m01, |
| // dy/du = m10, dy/dv = m11 |
| // dw/du = m30, dw/dv = m31 |
| // |
| // df/du = (dx/du*w - x*dw/du)/w^2 = (m00*w - m30*x)/w^2 |
| // df/dv = (dx/dv*w - x*dw/dv)/w^2 = (m01*w - m31*x)/w^2 |
| // dg/du = (dy/du*w - y*dw/du)/w^2 = (m10*w - m30*y)/w^2 |
| // dg/dv = (dy/dv*w - y*dw/du)/w^2 = (m11*w - m31*y)/w^2 |
| // |
| // Singular values of [df/du df/dv] define perspective correct minimum and maximum scale factors |
| // [dg/du dg/dv] |
| // for M evaluated at (u,v) |
| static float local_aa_radius(const SkM44& matrix, const SkV2& p) { |
| SkV4 devP = matrix.map(p.x, p.y, 0.f, 1.f); |
| |
| const float dxdu = matrix.rc(0,0); |
| const float dxdv = matrix.rc(0,1); |
| const float dydu = matrix.rc(1,0); |
| const float dydv = matrix.rc(1,1); |
| const float dwdu = matrix.rc(3,0); |
| const float dwdv = matrix.rc(3,1); |
| |
| float invW2 = 1.f / (devP.w * devP.w); |
| // non-persp has invW2 = 1, devP.w = 1, dwdu = 0, dwdv = 0 |
| float dfdu = (devP.w*dxdu - devP.x*dwdu) * invW2; // non-persp -> dxdu -> m00 |
| float dfdv = (devP.w*dxdv - devP.x*dwdv) * invW2; // non-persp -> dxdv -> m01 |
| float dgdu = (devP.w*dydu - devP.y*dwdu) * invW2; // non-persp -> dydu -> m10 |
| float dgdv = (devP.w*dydv - devP.y*dwdv) * invW2; // non-persp -> dydv -> m11 |
| |
| // no-persp, this is the singular values of [m00,m01][m10,m11], which is just the upper 2x2 |
| // and equivalent to SkMatrix::getMinmaxScales(). |
| auto [sv1, sv2] = singular_values(dfdu, dfdv, dgdu, dgdv); |
| |
| // The minimum and maximum singular values of the above matrix represent the min and maximum |
| // scale factors that could be applied by the 'matrix'. So if 'p' is moved 1px locally it will |
| // move between [min, max]px after transformation. Thus, moving 1/min px locally will move |
| // between [1, max/min]px after transformation, ensuring the device-space offset exceeds the |
| // minimum AA offset for analytic AA. |
| float minScale = std::min(sv1, sv2); |
| return kAARadius / minScale; |
| } |
| |
| static constexpr float kMiterScale = 1.f; |
| static constexpr float kBevelScale = 0.0f; |
| static constexpr float kRoundScale = SK_FloatSqrt2 - 1.f; |
| |
| struct LocalCornerVert { |
| SkV2 fPosition; // In unit square that each corner is normalized to |
| SkV2 fNormal; // Direction that AA outset is applied in |
| |
| float fStrokeScale; // Signed scale factor applied to external stroke radius, should be [-1,1] |
| float fMirrorScale; // Scale fPosition.yx, along with external join-scale, should be [0,1]. |
| float fCenterWeight; // Added to external center scale, > 0 forces point to center instead. |
| |
| // 'cornerMapping' is a row-major 2x2 matrix [[x y], [z w]] to flip and rotate the normalized |
| // positions into the local coord space. |
| SkV3 transform(const SkM44& m, const SkV4& cornerMapping, const SkV2& cornerPt, |
| const SkV2& cornerRadii, const SkV4& devCenter, float centerWeight, |
| float strokeRadius, float joinScale, float localAARadius) const { |
| const bool snapToCenter = centerWeight + fCenterWeight > 0.f; |
| if (snapToCenter) { |
| return {devCenter.x, devCenter.y, devCenter.w}; |
| } else { |
| // Normalized position before any additional AA offsets |
| SkV2 normalizedPos = fPosition + joinScale*fMirrorScale*SkV2{fPosition.y, fPosition.x}; |
| // scales the normalized unit corner to the actual radii of the corner, before any AA |
| // offsets are added. |
| SkV2 scale = cornerRadii + SkV2{fStrokeScale*strokeRadius, fStrokeScale*strokeRadius}; |
| normalizedPos = scale*normalizedPos - cornerRadii; |
| |
| if (fStrokeScale < 0.f) { |
| // An inset, which means it might cross over or might be forced to the center |
| SkV2 maxInset = scale - SkV2{localAARadius, localAARadius}; |
| if (maxInset.x < 0.f || maxInset.y < 0.f) { |
| normalizedPos = |
| SkV2{std::min(maxInset.x, 0.f), std::min(maxInset.y, 0.f)} |
| - cornerRadii; |
| } else { |
| normalizedPos += localAARadius * fNormal; |
| } |
| } // else no normal offsetting, or device-space offsetting |
| |
| SkV2 localPos = |
| {cornerMapping.x*normalizedPos.x + cornerMapping.y*normalizedPos.y + cornerPt.x, |
| cornerMapping.z*normalizedPos.x + cornerMapping.w*normalizedPos.y + cornerPt.y}; |
| SkV4 devPos = m.map(localPos.x, localPos.y, 0.f, 1.f); |
| |
| const bool deviceSpaceNormal = |
| fStrokeScale > 0.f && (fNormal.x > 0.f || fNormal.y > 0.f); |
| if (deviceSpaceNormal) { |
| SkV2 devNorm; |
| { |
| // To calculate a device-space normal, we use the normal matrix (A^-1)^T where |
| // A is CTM * T(cornerPt) * cornerMapping * scale. We inline the calculation |
| // of (T(cornerPt)*cornerMapping*scale)^-1^T * [nx, ny, 0, 0] = N', which means |
| // that CTM^-1^T * N' is equivalent to N'^T*CTM^-1, which can be calculated with |
| // two dot products if the CTM inverse is uploaded to the GPU. |
| |
| // We add epsilon so that rectangular corners are not degenerate, and circular |
| // corners remain unmodified. This only slightly increases inaccuracy for |
| // elliptical corners. |
| float sx = (scale.y + SK_ScalarNearlyZero) / (scale.x + SK_ScalarNearlyZero); |
| // Needed to calculate intermediate W of transformed normal. |
| float px = cornerMapping.y*cornerPt.y - cornerMapping.w*cornerPt.x; |
| float py = cornerMapping.z*cornerPt.x - cornerMapping.x*cornerPt.y; |
| // Inverse CTM, presumably calculated once as a uniform |
| SkM44 inv; |
| SkAssertResult(m.invert(&inv)); |
| |
| SkV4 normX4 = { sx*cornerMapping.w*fNormal.x, |
| -sx*cornerMapping.y*fNormal.x, |
| 0.f, |
| sx*px*fNormal.x}; |
| SkV4 normY4 = {-cornerMapping.z*fNormal.y, |
| cornerMapping.x*fNormal.y, |
| 0.f, |
| py*fNormal.y}; |
| |
| SkV2 normX = {inv.col(0).dot(normX4), inv.col(1).dot(normX4)}; |
| SkV2 normY = {inv.col(0).dot(normY4), inv.col(1).dot(normY4)}; |
| |
| if (joinScale == kMiterScale && fNormal.x > 0.f && fNormal.y > 0.f) { |
| // normX and normY represent adjacent edges' normals, so if we normalize |
| // them before adding together, we'll have a vector that bisects the edge |
| // normals instead of a vector matching fNormal, which is what we want when |
| // we're at a miter corner. |
| normX = normX.normalize(); |
| normY = normY.normalize(); |
| if (normX.dot(normY) < -0.8) { |
| // Nearly opposite directions, so the sum could have cancellation, so |
| // instead bisect orthogonal vectors and flip to keep consistent |
| float sign = normX.cross(normY) >= 0.f ? 1.f : -1.f; |
| normX = sign*SkV2{-normX.y, normX.x}; |
| normY = sign*SkV2{normY.y, -normY.x}; |
| } |
| } |
| |
| devNorm = (normX + normY).normalize(); |
| } |
| |
| // The local coordinates for a device-space AA outset are clamped to the non-outset |
| // point, which means we don't care about remaining in the same pre-homogenous |
| // divide plane. This makes it very easy to determine a homogenous coordinate that |
| // projects to the correct device-space position. |
| devPos.x += devPos.w * kAARadius * devNorm.x; |
| devPos.y += devPos.w * kAARadius * devNorm.y; |
| } |
| |
| return SkV3{devPos.x, devPos.y, devPos.w}; |
| } |
| } |
| }; |
| |
| static constexpr float kHR2 = SK_ScalarRoot2Over2; // "half root 2" |
| |
| static constexpr LocalCornerVert kCornerTemplate[19] = { |
| // Stroke-scale should be -1, 0, or 1. |
| // Mirror-scale should be 0 or 1. |
| // Center-weight should be -2 to never snap to center, -1 to snap when stroke coords would |
| // overlap, and 0 to snap for fill-style or overlapping coords. |
| // Local-aa-scale should be 0 or 1. |
| |
| // position, normal, stroke-scale mirror-scale center-weight |
| // Device-space AA outsets from outer curve |
| { {0.0f, 1.0f}, { 0.0f, 1.0f}, 1.0f, 0.0f, -2.f }, |
| { {0.0f, 1.0f}, { 0.0f, 1.0f}, 1.0f, 1.0f, -2.f }, |
| { {0.0f, 1.0f}, { kHR2, kHR2}, 1.0f, 1.0f, -2.f }, |
| { {1.0f, 0.0f}, { kHR2, kHR2}, 1.0f, 1.0f, -2.f }, |
| { {1.0f, 0.0f}, { 1.0f, 0.0f}, 1.0f, 1.0f, -2.f }, |
| { {1.0f, 0.0f}, { 1.0f, 0.0f}, 1.0f, 0.0f, -2.f }, |
| |
| // Outer anchors (no local or device-space normal outset) |
| { {0.0f, 1.0f}, { 0.0f, 0.0f}, 1.0f, 0.0f, -2.f }, |
| { {0.0f, 1.0f}, { 0.0f, 0.0f}, 1.0f, 1.0f, -2.f }, |
| { {1.0f, 0.0f}, { 0.0f, 0.0f}, 1.0f, 1.0f, -2.f }, |
| { {1.0f, 0.0f}, { 0.0f, 0.0f}, 1.0f, 0.0f, -2.f }, |
| |
| // Center of stroke (equivalent to outer anchors when filling) |
| { {0.0f, 1.0f}, { 0.0f, 0.0f}, 0.0f, 0.0f, -2.f }, |
| { {0.0f, 1.0f}, { 0.0f, 0.0f}, 0.0f, 1.0f, -2.f }, |
| { {1.0f, 0.0f}, { 0.0f, 0.0f}, 0.0f, 1.0f, -2.f }, |
| { {1.0f, 0.0f}, { 0.0f, 0.0f}, 0.0f, 0.0f, -2.f }, |
| |
| // Inner AA insets from inner curve |
| { {0.0f, 1.0f}, { 0.0f, -1.0f}, -1.0f, 0.0f, -1.f }, |
| { {0.5f, 0.5f}, {-kHR2, -kHR2}, -1.0f, 1.0f, -1.f }, |
| { {1.0f, 0.0f}, {-1.0f, 0.0f}, -1.0f, 0.0f, -1.f }, |
| |
| // Center filling vertices (equal to inner AA insets unless center-weight = 1) |
| { {0.5f, 0.5f}, {-kHR2, -kHR2}, -1.0f, 1.0f, 0.f }, |
| { {1.0f, 0.0f}, {-1.0f, 0.0f}, -1.0f, 0.0f, 0.f }, |
| }; |
| |
| static void compute_corner(SkV3 devPts[19], const SkM44& m, const SkV4& cornerMapping, |
| const SkV2& cornerPt, const SkV2& cornerRadii, const SkV4& center, |
| float centerWeight, float localAARadius, float strokeRadius, |
| SkPaint::Join join) { |
| float joinScale; |
| |
| // TODO: checking against localAARadius can snap to rect corner unexpectedly under high skew |
| // because localAARadius gets so big, but would be nice to be fuzzy here. |
| if (cornerRadii.x <= 0.f || cornerRadii.y <= 0.f) { |
| // Effectively a rectangular corner |
| joinScale = kMiterScale; // default for rect corners |
| if (strokeRadius > 0.f) { |
| // Non-hairline strokes need to adjust the join scale factor to match style. |
| if (join == SkPaint::kBevel_Join) { |
| joinScale = kBevelScale; |
| } else if (join == SkPaint::kRound_Join) { |
| joinScale = kRoundScale; |
| } |
| } |
| } else { |
| // Rounded filled corner vertices are always positioned for a round join since the |
| // underlying geometry has no real tangent discontinuity. |
| joinScale = kRoundScale; |
| } |
| |
| for (size_t i = 0; i < std::size(kCornerTemplate); ++i) { |
| devPts[i] = kCornerTemplate[i].transform(m, cornerMapping, cornerPt, cornerRadii, |
| center, centerWeight, strokeRadius, joinScale, |
| localAARadius); |
| } |
| } |
| |
| static const uint16_t kBR = 0*std::size(kCornerTemplate); |
| static const uint16_t kTR = 1*std::size(kCornerTemplate); |
| static const uint16_t kTL = 2*std::size(kCornerTemplate); |
| static const uint16_t kBL = 3*std::size(kCornerTemplate); |
| static const size_t kVertexCount = 4*std::size(kCornerTemplate); |
| static void compute_vertices(SkV3 devPts[kVertexCount], |
| const SkM44& m, |
| const SkRRect& rrect, |
| float strokeRadius, |
| SkPaint::Join join) { |
| SkV4 devCenter = m.map(rrect.getBounds().centerX(), rrect.getBounds().centerY(), 0.f, 1.f); |
| |
| float localAARadius = std::max({ |
| local_aa_radius(m, {rrect.getBounds().fRight, rrect.getBounds().fBottom}), |
| local_aa_radius(m, {rrect.getBounds().fRight, rrect.getBounds().fTop}), |
| local_aa_radius(m, {rrect.getBounds().fLeft, rrect.getBounds().fTop}), |
| local_aa_radius(m, {rrect.getBounds().fLeft, rrect.getBounds().fBottom}) |
| }); |
| |
| float centerWeight = 0.f; // No center snapping |
| if (strokeRadius < 0.f) { |
| // A fill, so inner vertices need to snap to the center and then adjust the stroke radius |
| // to 0 for later math to work out nicely. |
| strokeRadius = 0.f; |
| centerWeight = 1.f; |
| } |
| |
| // Check if the inset amount (max stroke-radius + local-aa-radius) would interfere with the |
| // opposite edge's inset or interfere with the adjacent corner's curve. When this happens, snap |
| // all the interior vertices to the center and let the fragment shader work through it. |
| // TODO: Could force centerWeight = 2 for filled rects and quads for simplicity around non |
| // orthogonal inset overlap calculations. |
| float maxInset = strokeRadius + localAARadius; |
| if (maxInset >= rrect.width() - maxInset || // L/R stroke insets would cross over |
| maxInset >= rrect.height() - maxInset || // T/B stroke insets would cross over |
| maxInset >= rrect.width() - rrect.radii(SkRRect::kLowerLeft_Corner).fX || // X corner cross |
| maxInset >= rrect.width() - rrect.radii(SkRRect::kLowerRight_Corner).fX || |
| maxInset >= rrect.width() - rrect.radii(SkRRect::kUpperLeft_Corner).fX || |
| maxInset >= rrect.width() - rrect.radii(SkRRect::kUpperRight_Corner).fX || |
| maxInset >= rrect.height() - rrect.radii(SkRRect::kLowerLeft_Corner).fY || // Y corner cross |
| maxInset >= rrect.height() - rrect.radii(SkRRect::kLowerRight_Corner).fY || |
| maxInset >= rrect.height() - rrect.radii(SkRRect::kUpperLeft_Corner).fY || |
| maxInset >= rrect.height() - rrect.radii(SkRRect::kUpperRight_Corner).fY) { |
| // All interior vertices need to snap to the center |
| centerWeight = 2.f; |
| } |
| |
| // The normalized corner template is defined relative to the quarter circle with positive X |
| // and positive Y, with a counter clockwise winding (if +Y points down). This corresponds to |
| // the bottom-right corner. |
| static constexpr SkV4 kBRBasis = { 1.f, 0.f, 0.f, 1.f}; |
| static constexpr SkV4 kTRBasis = { 0.f, 1.f, -1.f, 0.f}; |
| static constexpr SkV4 kTLBasis = {-1.f, 0.f, 0.f, -1.f}; |
| static constexpr SkV4 kBLBasis = { 0.f, -1.f, 1.f, 0.f}; |
| |
| compute_corner(devPts + kBR, m, kBRBasis, |
| {rrect.getBounds().fRight, |
| rrect.getBounds().fBottom}, |
| {rrect.radii(SkRRect::kLowerRight_Corner).fX, |
| rrect.radii(SkRRect::kLowerRight_Corner).fY}, |
| devCenter, centerWeight, localAARadius, strokeRadius, join); |
| compute_corner(devPts + kTR, m, kTRBasis, |
| {rrect.getBounds().fRight, |
| rrect.getBounds().fTop}, |
| {rrect.radii(SkRRect::kUpperRight_Corner).fY, |
| rrect.radii(SkRRect::kUpperRight_Corner).fX}, |
| devCenter, centerWeight, localAARadius,strokeRadius, join); |
| compute_corner(devPts + kTL, m, kTLBasis, |
| {rrect.getBounds().fLeft, |
| rrect.getBounds().fTop}, |
| {rrect.radii(SkRRect::kUpperLeft_Corner).fX, |
| rrect.radii(SkRRect::kUpperLeft_Corner).fY}, |
| devCenter, centerWeight, localAARadius,strokeRadius, join); |
| compute_corner(devPts + kBL, m, kBLBasis, |
| {rrect.getBounds().fLeft, |
| rrect.getBounds().fBottom}, |
| {rrect.radii(SkRRect::kLowerLeft_Corner).fY, |
| rrect.radii(SkRRect::kLowerLeft_Corner).fX}, |
| devCenter, centerWeight, localAARadius,strokeRadius, join); |
| } |
| |
| // All indices |
| static const uint16_t kIndices[] = { |
| // Exterior AA ramp outset |
| kBR+0,kBR+6,kBR+1,kBR+7,kBR+2,kBR+8,kBR+3,kBR+8,kBR+4,kBR+9,kBR+5,kBR+9, |
| kTR+0,kTR+6,kTR+1,kTR+7,kTR+2,kTR+8,kTR+3,kTR+8,kTR+4,kTR+9,kTR+5,kTR+9, |
| kTL+0,kTL+6,kTL+1,kTL+7,kTL+2,kTL+8,kTL+3,kTL+8,kTL+4,kTL+9,kTL+5,kTL+9, |
| kBL+0,kBL+6,kBL+1,kBL+7,kBL+2,kBL+8,kBL+3,kBL+8,kBL+4,kBL+9,kBL+5,kBL+9, |
| kBR+0,kBR+6,kBR+6, // close and extra vertex to jump to next strip |
| // Outer to central curve |
| kBR+6,kBR+10,kBR+7,kBR+11,kBR+8,kBR+12,kBR+9,kBR+13, |
| kTR+6,kTR+10,kTR+7,kTR+11,kTR+8,kTR+12,kTR+9,kTR+13, |
| kTL+6,kTL+10,kTL+7,kTL+11,kTL+8,kTL+12,kTL+9,kTL+13, |
| kBL+6,kBL+10,kBL+7,kBL+11,kBL+8,kBL+12,kBL+9,kBL+13, |
| kBR+6,kBR+10,kBR+10, // close and extra vertex to jump to next strip |
| // Center to inner curve's insets |
| kBR+10,kBR+14,kBR+11,kBR+15,kBR+12,kBR+16,kBR+13,kBR+16, |
| kTR+10,kTR+14,kTR+11,kTR+15,kTR+12,kTR+16,kTR+13,kTR+16, |
| kTL+10,kTL+14,kTL+11,kTL+15,kTL+12,kTL+16,kTL+13,kTL+16, |
| kBL+10,kBL+14,kBL+11,kBL+15,kBL+12,kBL+16,kBL+13,kBL+16, |
| kBR+10,kBR+14,kBR+14, // close and extra vertex to jump to next strip |
| // Inner inset to center of shape |
| kBR+14,kBR+17,kBR+15,kBR+17,kBR+16,kBR+16,kBR+18,kTR+14, |
| kTR+14,kTR+17,kTR+15,kTR+17,kTR+16,kTR+16,kTR+18,kTL+14, |
| kTL+14,kTL+17,kTL+15,kTL+17,kTL+16,kTL+16,kTL+18,kBL+14, |
| kBL+14,kBL+17,kBL+15,kBL+17,kBL+16,kBL+16,kBL+18,kBR+14 // close |
| }; |
| |
| // Separated to draw with different colors (vs. duplicating vertices to change colors). |
| static const uint16_t kOuterCornerIndices[] = { |
| kBR+0, kBR+0,kBR+6,kBR+1,kBR+7,kBR+2,kBR+8,kBR+3,kBR+8,kBR+4,kBR+9,kBR+5, kBR+5, |
| kTR+0, kTR+0,kTR+6,kTR+1,kTR+7,kTR+2,kTR+8,kTR+3,kTR+8,kTR+4,kTR+9,kTR+5, kTR+5, |
| kTL+0, kTL+0,kTL+6,kTL+1,kTL+7,kTL+2,kTL+8,kTL+3,kTL+8,kTL+4,kTL+9,kTL+5, kTL+5, |
| kBL+0, kBL+0,kBL+6,kBL+1,kBL+7,kBL+2,kBL+8,kBL+3,kBL+8,kBL+4,kBL+9,kBL+5, kBL+5, |
| |
| kBR+6, kBR+6,kBR+10,kBR+7,kBR+11,kBR+8,kBR+12,kBR+9,kBR+13, kBR+13, |
| kTR+6, kTR+6,kTR+10,kTR+7,kTR+11,kTR+8,kTR+12,kTR+9,kTR+13, kTR+13, |
| kTL+6, kTL+6,kTL+10,kTL+7,kTL+11,kTL+8,kTL+12,kTL+9,kTL+13, kTL+13, |
| kBL+6, kBL+6,kBL+10,kBL+7,kBL+11,kBL+8,kBL+12,kBL+9,kBL+13, kBL+13 |
| }; |
| |
| static const uint16_t kInnerCornerIndices[] = { |
| kBR+10, kBR+10,kBR+14,kBR+11,kBR+15,kBR+12,kBR+16,kBR+13, kBR+13, |
| kTR+10, kTR+10,kTR+14,kTR+11,kTR+15,kTR+12,kTR+16,kTR+13, kTR+13, |
| kTL+10, kTL+10,kTL+14,kTL+11,kTL+15,kTL+12,kTL+16,kTL+13, kTL+13, |
| kBL+10, kBL+10,kBL+14,kBL+11,kBL+15,kBL+12,kBL+16,kBL+13, kBL+13, |
| }; |
| |
| static const uint16_t kInteriorIndices[] = { |
| kBR+14,kBR+17,kBR+15,kBR+17,kBR+16,kBR+16,kBR+18,kTR+14, |
| kTR+14,kTR+17,kTR+15,kTR+17,kTR+16,kTR+16,kTR+18,kTL+14, |
| kTL+14,kTL+17,kTL+15,kTL+17,kTL+16,kTL+16,kTL+18,kBL+14, |
| kBL+14,kBL+17,kBL+15,kBL+17,kBL+16,kBL+16,kBL+18,kBR+14 // close |
| }; |
| |
| // Implicit in the original mesh from the tri-strip connections between corners |
| static const uint16_t kEdgeIndices[] = { |
| kBR+5, kBR+5,kBR+9,kTR+0,kTR+6, kTR+6, |
| kBR+9, kBR+9,kBR+13,kTR+6,kTR+10, kTR+10, |
| kBR+13, kBR+13,kBR+16,kTR+10,kTR+14, kTR+14, |
| |
| kTR+5, kTR+5,kTR+9,kTL+0,kTL+6, kTL+6, |
| kTR+9, kTR+9,kTR+13,kTL+6,kTL+10, kTL+10, |
| kTR+13, kTR+13,kTR+16,kTL+10,kTL+14, kTL+14, |
| |
| kTL+5, kTL+5,kTL+9,kBL+0,kBL+6, kBL+6, |
| kTL+9, kTL+9,kTL+13,kBL+6,kBL+10, kBL+10, |
| kTL+13, kTL+13,kTL+16,kBL+10,kBL+14, kBL+14, |
| |
| kBL+5, kBL+5,kBL+9,kBR+0,kBR+6, kBR+6, |
| kBL+9, kBL+9,kBL+13,kBR+6,kBR+10, kBR+10, |
| kBL+13, kBL+13,kBL+16,kBR+10,kBR+14, kBR+14, |
| }; |
| |
| class GraphitePrimitivesSlide : public ClickHandlerSlide { |
| static constexpr float kControlPointRadius = 3.f; |
| static constexpr float kBaseScale = 50.f; |
| |
| public: |
| GraphitePrimitivesSlide() |
| : fOrigin{300.f, 300.f} |
| , fXAxisPoint{300.f + kBaseScale, 300.f} |
| , fYAxisPoint{300.f, 300.f + kBaseScale} |
| , fStrokeWidth{10.f} |
| , fJoinMode(SkPaint::kMiter_Join) |
| , fMode(PrimitiveMode::kFillRect) { |
| fName = "GraphitePrimitives"; |
| } |
| |
| void draw(SkCanvas* canvas) override { |
| canvas->save(); |
| SkM44 viewMatrix = canvas->getLocalToDevice(); |
| |
| canvas->concat(this->basisMatrix()); |
| |
| SkM44 totalMatrix = canvas->getLocalToDevice(); |
| |
| // Base shape + style |
| SkRRect rrect = this->primitiveShape(); |
| canvas->drawRRect(rrect, paint(SK_ColorBLUE, this->strokeWidth(), fJoinMode)); |
| canvas->restore(); |
| |
| canvas->save(); |
| canvas->resetMatrix(); |
| // Draw the full mesh directly in device space |
| this->drawVertices(canvas, totalMatrix); |
| // Draw the controls in device space so we get consistent circles for the click points. |
| SkV4 origin = viewMatrix.map(fOrigin.x, fOrigin.y, 0.f, 1.f); |
| SkV4 xAxis = viewMatrix.map(fXAxisPoint.x, fXAxisPoint.y, 0.f, 1.f); |
| SkV4 yAxis = viewMatrix.map(fYAxisPoint.x, fYAxisPoint.y, 0.f, 1.f); |
| |
| // Axes |
| canvas->drawLine({origin.x/origin.w, origin.y/origin.w}, |
| {xAxis.x/xAxis.w, xAxis.y/xAxis.w}, paint(SK_ColorRED, 0.f)); |
| canvas->drawLine({origin.x/origin.w, origin.y/origin.w}, |
| {yAxis.x/yAxis.w, yAxis.y/yAxis.w}, paint(SK_ColorGREEN, 0.f)); |
| |
| // Control points |
| canvas->drawCircle({origin.x/origin.w, origin.y/origin.w}, |
| kControlPointRadius, paint(SK_ColorBLACK)); |
| canvas->drawCircle({xAxis.x/xAxis.w, xAxis.y/xAxis.w}, |
| kControlPointRadius, paint(SK_ColorRED)); |
| canvas->drawCircle({yAxis.x/yAxis.w, yAxis.y/yAxis.w}, |
| kControlPointRadius, paint(SK_ColorGREEN)); |
| canvas->restore(); |
| } |
| |
| bool onChar(SkUnichar) override; |
| |
| protected: |
| Click* onFindClickHandler(SkScalar x, SkScalar y, skui::ModifierKey) override; |
| bool onClick(Click*) override; |
| |
| private: |
| class Click; |
| |
| enum class PrimitiveMode { |
| kFillRect, |
| kFillRRect, |
| kStrokeRect, |
| kStrokeRRect |
| }; |
| |
| // Computed from 3 control points. Concat with CTM to get total matrix. |
| SkM44 basisMatrix() const { |
| SkV2 xAxis = (fXAxisPoint - fOrigin) / kBaseScale; |
| SkV2 yAxis = (fYAxisPoint - fOrigin) / kBaseScale; |
| |
| return SkM44::Cols({xAxis.x, xAxis.y, 0.f, 0.f}, |
| {yAxis.x, yAxis.y, 0.f, 0.f}, |
| {0.f, 0.f, 1.f, 0.f}, |
| {fOrigin.x, fOrigin.y, 0.f, 1.f}); |
| } |
| |
| float strokeWidth() const { |
| if (fMode == PrimitiveMode::kFillRect || fMode == PrimitiveMode::kFillRRect) { |
| return -1.f; |
| } |
| return fStrokeWidth; |
| } |
| |
| SkRRect primitiveShape() const { |
| static const SkRect kOuterBounds = SkRect::MakeLTRB(-kBaseScale, -kBaseScale, |
| kBaseScale, kBaseScale); |
| // Filled rounded rects can have arbitrary corners |
| static const SkVector kOuterRadii[4] = { { 0.25f * kBaseScale, 0.75f * kBaseScale }, |
| { 0.f, 0.f}, |
| { 0.5f * kBaseScale, 0.5f * kBaseScale }, |
| { 0.75f * kBaseScale, 0.25f * kBaseScale } }; |
| // // Stroked rounded rects will only have circular corners |
| static const SkVector kStrokeRadii[4] = { { 0.25f * kBaseScale, 0.25f * kBaseScale }, |
| { 0.f, 0.f }, |
| { 0.5f * kBaseScale, 0.5f * kBaseScale }, |
| { 0.75f * kBaseScale, 0.75f * kBaseScale } }; |
| |
| float strokeRadius = 0.5f * fStrokeWidth; |
| switch(fMode) { |
| case PrimitiveMode::kFillRect: |
| return SkRRect::MakeRect(kOuterBounds.makeOutset(strokeRadius, strokeRadius)); |
| case PrimitiveMode::kFillRRect: { |
| SkRRect rrect; |
| rrect.setRectRadii(kOuterBounds, kOuterRadii); |
| rrect.outset(strokeRadius, strokeRadius); |
| return rrect; } |
| case PrimitiveMode::kStrokeRect: |
| return SkRRect::MakeRect(kOuterBounds); |
| case PrimitiveMode::kStrokeRRect: { |
| SkRRect rrect; |
| rrect.setRectRadii(kOuterBounds, kStrokeRadii); |
| return rrect; |
| } |
| } |
| |
| SkUNREACHABLE; |
| } |
| |
| void drawVertices(SkCanvas* canvas, const SkM44& ctm) { |
| SkRRect rrect = this->primitiveShape(); |
| float strokeRadius = 0.5f * this->strokeWidth(); |
| |
| SkV3 points[kVertexCount]; |
| SkPoint vertices[kVertexCount]; |
| compute_vertices(points, ctm, rrect, strokeRadius, fJoinMode); |
| // SkCanvas::drawVertices() wants SkPoint, but normally we'd let the GPU handle the |
| // perspective division and clipping. |
| for (size_t i = 0; i < kVertexCount; ++i) { |
| vertices[i] = SkPoint{points[i].x/points[i].z, points[i].y/points[i].z}; |
| } |
| |
| auto drawMeshSubset = [vertices, canvas](SkColor color, |
| const uint16_t* indices, |
| size_t indexCount) { |
| sk_sp<SkVertices> mesh = SkVertices::MakeCopy( |
| SkVertices::kTriangleStrip_VertexMode, kVertexCount, vertices, |
| nullptr, nullptr, (int) indexCount, indices); |
| SkPaint meshPaint; |
| meshPaint.setColor(color); |
| meshPaint.setAlphaf(0.5f); |
| canvas->drawVertices(mesh, SkBlendMode::kSrc, meshPaint); |
| }; |
| if (fColorize) { |
| drawMeshSubset(SK_ColorGRAY, |
| kEdgeIndices, |
| std::size(kEdgeIndices)); |
| drawMeshSubset(SK_ColorDKGRAY, |
| kInteriorIndices, |
| std::size(kInteriorIndices)); |
| drawMeshSubset(SK_ColorMAGENTA, |
| kInnerCornerIndices, |
| std::size(kInnerCornerIndices)); |
| drawMeshSubset(SK_ColorCYAN, |
| kOuterCornerIndices, |
| std::size(kOuterCornerIndices)); |
| } else { |
| drawMeshSubset(SK_ColorGRAY, kIndices, std::size(kIndices)); |
| } |
| |
| // Draw the edges over the triangle strip mesh, but keep track of edges already drawn so |
| // that we don't oversaturate AA on edges shared by multiple triangles. |
| std::unordered_set<uint32_t> edges; |
| auto drawEdge = [&edges, vertices, canvas](uint16_t e0, uint16_t e1) { |
| uint32_t edgeID = (std::max(e0, e1) << 16) | std::min(e0, e1); |
| if (edges.find(edgeID) == edges.end()) { |
| edges.insert(edgeID); |
| if (SkScalarNearlyEqual(vertices[e0].fX, vertices[e1].fX) && |
| SkScalarNearlyEqual(vertices[e0].fY, vertices[e1].fY)) { |
| return; |
| } |
| canvas->drawLine(vertices[e0], vertices[e1], paint(SK_ColorBLACK, 0.f)); |
| } |
| }; |
| for (size_t i = 2; i < std::size(kIndices); ++i) { |
| drawEdge(kIndices[i-1], kIndices[i]); |
| drawEdge(kIndices[i-2], kIndices[i]); |
| } |
| } |
| |
| // This Sample is responsive to the entire transform of the viewer slide, including the |
| // transform (rotation, scale, and perspective) selected from the widget. The 3 points below |
| // define the location and basis of the local coordinate space, relative to the viewer's |
| // coordinate space. This is used instead of the root canvas coordinate space because it aligns |
| // with the coordinate space that the click handler operates in. |
| SkV2 fOrigin; |
| SkV2 fXAxisPoint; |
| SkV2 fYAxisPoint; |
| |
| float fStrokeWidth; |
| SkPaint::Join fJoinMode; |
| PrimitiveMode fMode; |
| bool fColorize = true; |
| }; |
| |
| class GraphitePrimitivesSlide::Click : public ClickHandlerSlide::Click { |
| public: |
| Click(SkV2* point) : fPoint(point) {} |
| |
| void drag() { |
| SkVector delta = fCurr - fPrev; |
| *fPoint += {delta.fX, delta.fY}; |
| } |
| |
| private: |
| SkV2* fPoint; |
| }; |
| |
| ClickHandlerSlide::Click* GraphitePrimitivesSlide::onFindClickHandler(SkScalar x, SkScalar y, |
| skui::ModifierKey) { |
| auto selected = [x,y](const SkV2& p) { |
| return ((p - SkV2{x,y}).length() < kControlPointRadius); |
| }; |
| |
| if (selected(fOrigin)) { |
| return new Click(&fOrigin); |
| } else if (selected(fXAxisPoint)) { |
| return new Click(&fXAxisPoint); |
| } else if (selected(fYAxisPoint)) { |
| return new Click(&fYAxisPoint); |
| } else { |
| return nullptr; |
| } |
| } |
| |
| bool GraphitePrimitivesSlide::onClick(ClickHandlerSlide::Click* click) { |
| Click* myClick = (Click*) click; |
| myClick->drag(); |
| return true; |
| } |
| |
| bool GraphitePrimitivesSlide::onChar(SkUnichar code) { |
| switch(code) { |
| case '1': |
| fMode = PrimitiveMode::kFillRect; |
| return true; |
| case '2': |
| fMode = PrimitiveMode::kFillRRect; |
| return true; |
| case '3': |
| fMode = PrimitiveMode::kStrokeRect; |
| return true; |
| case '4': |
| fMode = PrimitiveMode::kStrokeRRect; |
| return true; |
| case '-': |
| fStrokeWidth = std::max(0.f, fStrokeWidth - 0.4f); |
| return true; |
| case '=': |
| fStrokeWidth = std::min(5 * kBaseScale, fStrokeWidth + 0.4f); |
| return true; |
| case 'q': |
| fJoinMode = SkPaint::kRound_Join; |
| return true; |
| case 'w': |
| fJoinMode = SkPaint::kBevel_Join; |
| return true; |
| case 'e': |
| fJoinMode = SkPaint::kMiter_Join; |
| return true; |
| case 'r': |
| fStrokeWidth = 10.f; |
| fOrigin = {300.f, 300.f}; |
| fXAxisPoint = {300.f + kBaseScale, 300.f}; |
| fYAxisPoint = {300.f, 300.f + kBaseScale}; |
| return true; |
| case 'c': |
| fColorize = !fColorize; |
| return true; |
| } |
| return false; |
| } |
| |
| DEF_SLIDE(return new GraphitePrimitivesSlide();) |
