mirror of
https://github.com/openharmony/graphic_ui.git
synced 2026-06-30 23:17:56 -04:00
mamingshuai
121 lines
3.7 KiB
C++
Executable File
121 lines
3.7 KiB
C++
Executable File
/*
|
|
* Copyright (c) 2020-2021 Huawei Device Co., Ltd.
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#include "draw/draw_triangle.h"
|
|
#include "draw/draw_utils.h"
|
|
|
|
namespace OHOS {
|
|
void DrawTriangle::Draw(const Point* points, uint8_t count, const Rect& mask, const ColorType& color, OpacityType opa)
|
|
{
|
|
if ((points == nullptr) || (count != VERTEX_NUM)) {
|
|
return;
|
|
}
|
|
// sort vertex according to y axis
|
|
Point p1 = points[0]; // 0: point index
|
|
Point p2 = points[1]; // 1: point index
|
|
Point p3 = points[2]; // 2: point index
|
|
// return if vertexs are invalid.
|
|
if ((p1.x == p2.x) && ((p1.y == p2.y) || (p1.x == p3.x))) {
|
|
return;
|
|
}
|
|
if ((p2.x == p3.x) && (p2.y == p3.y)) {
|
|
return;
|
|
}
|
|
if (((p1.x == p3.x) || (p1.y == p2.y)) && (p1.y == p3.y)) {
|
|
return;
|
|
}
|
|
SortVertexs(p1, p2, p3);
|
|
Edge edge1 = InitEdge(p1, p2);
|
|
Edge edge2 = InitEdge(p1, p3);
|
|
Rect area;
|
|
int16_t lastY = p1.y;
|
|
|
|
while (edge1.curPoint.y <= p3.y) {
|
|
// change edge1 from p1-p2 to p2-p3
|
|
if (edge1.curPoint.y == p2.y) {
|
|
edge1 = InitEdge(p2, p3);
|
|
if (edge1.dPoint.y == 0) {
|
|
return;
|
|
}
|
|
}
|
|
|
|
area.SetLeft(MATH_MIN(edge1.curPoint.x, edge2.curPoint.x));
|
|
area.SetRight(MATH_MAX(edge1.curPoint.x, edge2.curPoint.x));
|
|
area.SetTop(MATH_MIN(edge1.curPoint.y, edge2.curPoint.y));
|
|
area.SetBottom(MATH_MAX(edge1.curPoint.y, edge2.curPoint.y));
|
|
DrawUtils::GetInstance()->DrawColorArea(area, mask, color, opa);
|
|
|
|
while (edge1.curPoint.y == lastY) {
|
|
// use Bresenham algorithm to get next point on edge1
|
|
StepToNextPointOnEdge(edge1);
|
|
}
|
|
while (edge2.curPoint.y == lastY) {
|
|
// use Bresenham algorithm to get next point on edge2
|
|
StepToNextPointOnEdge(edge2);
|
|
}
|
|
lastY = edge1.curPoint.y;
|
|
}
|
|
}
|
|
|
|
void DrawTriangle::SortVertexs(Point& p1, Point& p2, Point& p3)
|
|
{
|
|
SortPoint(p1, p2);
|
|
SortPoint(p2, p3);
|
|
SortPoint(p1, p2);
|
|
}
|
|
|
|
void DrawTriangle::SortPoint(Point& p1, Point& p2)
|
|
{
|
|
Point temp;
|
|
if (p1.y > p2.y) {
|
|
temp = p1;
|
|
p1 = p2;
|
|
p2 = temp;
|
|
}
|
|
}
|
|
|
|
void DrawTriangle::StepToNextPointOnEdge(Edge& edge)
|
|
{
|
|
if (edge.dPoint.x > edge.dPoint.y) {
|
|
edge.curPoint.x += edge.uPoint.x;
|
|
edge.eps += edge.dPoint.y;
|
|
if ((edge.eps << 1) >= edge.dPoint.x) {
|
|
edge.curPoint.y += edge.uPoint.y;
|
|
edge.eps -= edge.dPoint.x;
|
|
}
|
|
} else {
|
|
edge.curPoint.y += edge.uPoint.y;
|
|
edge.eps += edge.dPoint.x;
|
|
if ((edge.eps << 1) >= edge.dPoint.y) {
|
|
edge.curPoint.x += edge.uPoint.x;
|
|
edge.eps -= edge.dPoint.y;
|
|
}
|
|
}
|
|
}
|
|
|
|
DrawTriangle::Edge DrawTriangle::InitEdge(const Point& startP, const Point& endP)
|
|
{
|
|
Edge edge = { {0, 0}, {0, 0}, {0, 0}, 0 };
|
|
edge.curPoint = startP;
|
|
edge.dPoint.x = startP.x - endP.x;
|
|
edge.dPoint.y = startP.y - endP.y;
|
|
edge.uPoint.x = (edge.dPoint.x < 0) ? 1 : -1;
|
|
edge.uPoint.y = (edge.dPoint.y < 0) ? 1 : -1;
|
|
edge.eps = 0;
|
|
edge.dPoint.x = MATH_ABS(edge.dPoint.x);
|
|
edge.dPoint.y = MATH_ABS(edge.dPoint.y);
|
|
return edge;
|
|
}
|
|
} // namespace OHOS
|