diff options
Diffstat (limited to 'src/platform/graphics')
| -rw-r--r-- | src/platform/graphics/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | src/platform/graphics/Geometry.cpp | 156 |
2 files changed, 157 insertions, 0 deletions
diff --git a/src/platform/graphics/CMakeLists.txt b/src/platform/graphics/CMakeLists.txt index c668934d..1d983188 100644 --- a/src/platform/graphics/CMakeLists.txt +++ b/src/platform/graphics/CMakeLists.txt @@ -1,5 +1,6 @@ add_library(cru_platform_graphics SHARED ForDllExport.cpp + Geometry.cpp NullPainter.cpp ) target_compile_definitions(cru_platform_graphics PRIVATE CRU_PLATFORM_GRAPHICS_EXPORT_API) diff --git a/src/platform/graphics/Geometry.cpp b/src/platform/graphics/Geometry.cpp new file mode 100644 index 00000000..a9a93bf4 --- /dev/null +++ b/src/platform/graphics/Geometry.cpp @@ -0,0 +1,156 @@ +#include "cru/platform/graphics/Geometry.h" + +#include <cmath> + +namespace cru::platform::graphics { +constexpr float PI = 3.14159265358979323846f; + +using std::abs; +using std::atan2; +using std::ceil; +using std::cos; +using std::sin; +using std::sqrt; + +// The following codes are from Qt. + +static void pathArcSegment(IGeometryBuilder* path, float xc, float yc, + float th0, float th1, float rx, float ry, + float xAxisRotation) { + float sinTh, cosTh; + float a00, a01, a10, a11; + float x1, y1, x2, y2, x3, y3; + float t; + float thHalf; + + sinTh = sin(xAxisRotation * (PI / 180.0)); + cosTh = cos(xAxisRotation * (PI / 180.0)); + + a00 = cosTh * rx; + a01 = -sinTh * ry; + a10 = sinTh * rx; + a11 = cosTh * ry; + + thHalf = 0.5 * (th1 - th0); + t = (8.0 / 3.0) * sin(thHalf * 0.5) * sin(thHalf * 0.5) / sin(thHalf); + x1 = xc + cos(th0) - t * sin(th0); + y1 = yc + sin(th0) + t * cos(th0); + x3 = xc + cos(th1); + y3 = yc + sin(th1); + x2 = x3 + t * sin(th1); + y2 = y3 - t * cos(th1); + + path->CubicBezierTo({a00 * x1 + a01 * y1, a10 * x1 + a11 * y1}, + {a00 * x2 + a01 * y2, a10 * x2 + a11 * y2}, + {a00 * x3 + a01 * y3, a10 * x3 + a11 * y3}); +} + +// the arc handling code underneath is from XSVG (BSD license) +/* + * Copyright 2002 USC/Information Sciences Institute + * + * Permission to use, copy, modify, distribute, and sell this software + * and its documentation for any purpose is hereby granted without + * fee, provided that the above copyright notice appear in all copies + * and that both that copyright notice and this permission notice + * appear in supporting documentation, and that the name of + * Information Sciences Institute not be used in advertising or + * publicity pertaining to distribution of the software without + * specific, written prior permission. Information Sciences Institute + * makes no representations about the suitability of this software for + * any purpose. It is provided "as is" without express or implied + * warranty. + * + * INFORMATION SCIENCES INSTITUTE DISCLAIMS ALL WARRANTIES WITH REGARD + * TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL INFORMATION SCIENCES + * INSTITUTE BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL + * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA + * OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER + * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + * + */ +static void pathArc(IGeometryBuilder* path, float rx, float ry, + float x_axis_rotation, int large_arc_flag, int sweep_flag, + float x, float y, float curx, float cury) { + const float Pr1 = rx * rx; + const float Pr2 = ry * ry; + + if (!Pr1 || !Pr2) return; + + float sin_th, cos_th; + float a00, a01, a10, a11; + float x0, y0, x1, y1, xc, yc; + float d, sfactor, sfactor_sq; + float th0, th1, th_arc; + int i, n_segs; + float dx, dy, dx1, dy1, Px, Py, check; + + rx = abs(rx); + ry = abs(ry); + + sin_th = sin(x_axis_rotation * (PI / 180.0)); + cos_th = cos(x_axis_rotation * (PI / 180.0)); + + dx = (curx - x) / 2.0; + dy = (cury - y) / 2.0; + dx1 = cos_th * dx + sin_th * dy; + dy1 = -sin_th * dx + cos_th * dy; + Px = dx1 * dx1; + Py = dy1 * dy1; + /* Spec : check if radii are large enough */ + check = Px / Pr1 + Py / Pr2; + if (check > 1) { + rx = rx * sqrt(check); + ry = ry * sqrt(check); + } + + a00 = cos_th / rx; + a01 = sin_th / rx; + a10 = -sin_th / ry; + a11 = cos_th / ry; + x0 = a00 * curx + a01 * cury; + y0 = a10 * curx + a11 * cury; + x1 = a00 * x + a01 * y; + y1 = a10 * x + a11 * y; + /* (x0, y0) is current point in transformed coordinate space. + (x1, y1) is new point in transformed coordinate space. + The arc fits a unit-radius circle in this space. + */ + d = (x1 - x0) * (x1 - x0) + (y1 - y0) * (y1 - y0); + if (!d) return; + sfactor_sq = 1.0 / d - 0.25; + if (sfactor_sq < 0) sfactor_sq = 0; + sfactor = sqrt(sfactor_sq); + if (sweep_flag == large_arc_flag) sfactor = -sfactor; + xc = 0.5 * (x0 + x1) - sfactor * (y1 - y0); + yc = 0.5 * (y0 + y1) + sfactor * (x1 - x0); + /* (xc, yc) is center of the circle. */ + + th0 = atan2(y0 - yc, x0 - xc); + th1 = atan2(y1 - yc, x1 - xc); + + th_arc = th1 - th0; + if (th_arc < 0 && sweep_flag) + th_arc += 2 * PI; + else if (th_arc > 0 && !sweep_flag) + th_arc -= 2 * PI; + + n_segs = ceil(abs(th_arc / (PI * 0.5 + 0.001))); + + for (i = 0; i < n_segs; i++) { + pathArcSegment(path, xc, yc, th0 + i * th_arc / n_segs, + th0 + (i + 1) * th_arc / n_segs, rx, ry, x_axis_rotation); + } +} + +void IGeometryBuilder::ArcTo(const Point& radius, float angle, + bool is_large_arc, bool is_clockwise, + const Point& end_point) { + auto current_position = GetCurrentPosition(); + pathArc(this, radius.x, radius.y, angle, is_large_arc, is_clockwise, + end_point.x, end_point.y, current_position.x, current_position.y); +} + +} // namespace cru::platform::graphics |