基于python win32setpixel api怎么实现计算机图形学相关操作

本篇内容介绍了"基于python win32setpixel api怎么实现计算机图形学相关操作"的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！

扫描线填充过程

裁剪过程（根据鼠标位置，实时裁剪多边形，右边的蓝色是裁剪后的图形）

为什么选择win32 api画图

选择win32的原因是我想做一些与众不同的实现方法，比起用D3或者Echarts这种webGL的实现方式，我更想直接在显示器上画出图像，看起来更极客一些。这也导致了录屏软件没办法捕捉，只能用手机来录制????

为什么不选C++而选择python

主要是python能对内存做个管理，C++直接调这种底层的接口会把内存搞坏掉，导致电脑变得特别卡。。不信大家可以在电脑上编译运行这段代码2分钟试一试，如果你电脑没炸，算你有钱。。

#include // g++ a.cpp -o a.exe -lgdi32 && a.exevoid bresenham(int x0,int y0,int x1,int y1){    int dx = abs(x1-x0);    int dy = abs(y1-y0);    int sx = x0-dy){            err = err-dy;            x0 = x0+sx;        }        if(e2
画线
对于画线部分，我这里使用了一个叫bresenham算法。。虽然我念不出名字，但是这个算法能够帮助我们实现画线运算，还有后面的中心圆填充，多边形绘画等方法。而且不通过浮点数的运算，直接变成整数运算，算法实现的函数如下所示，看起来比较简单，运行速度也很快。
def bresenham(x0, y0, x1, y1 , color):    dx = abs(x1 - x0)    dy = abs(y1 - y0)    sx = 1 if x0 < x1 else -1    sy = 1 if y0 < y1 else -1    err = dx - dy    while True:        win32gui.SetPixel(dc, x0, y0, color)        if x0 == x1 and y0 == y1:            break        e2 = 2 * err        if e2 > -dy:            err -= dy            x0 += sx        if e2 < dx:            err += dx            y0 += sy
我的屏幕分辨率是1920x1080的，只要在电脑里调用这个函数，把两个点的坐标填进去，就可以在显示器屏幕上画一条线。
中心圆算法
这个中心圆算法相对来说就比画线的算法在理解上面难很多，但是实现起来更简单一些，分成8个关于直线的和坐标轴对称的区域画圆，因此知道一个就可以画出其他几个，下面是实现过程。
def draw_circle(x, y, r):    x0 = 0    y0 = r    d = 3 - 2 * r    while x0 <= y0:        win32gui.SetPixel(dc, x + x0, y + y0, 0xffffff)        win32gui.SetPixel(dc, x + y0, y + x0, 0xffffff)        win32gui.SetPixel(dc, x - y0, y + x0, 0xffffff)        win32gui.SetPixel(dc, x - x0, y + y0, 0xffffff)        win32gui.SetPixel(dc, x - x0, y - y0, 0xffffff)        win32gui.SetPixel(dc, x - y0, y - x0, 0xffffff)        win32gui.SetPixel(dc, x + y0, y - x0, 0xffffff)        win32gui.SetPixel(dc, x + x0, y - y0, 0xffffff)        if d < 0:            d += 4 * x0 + 6        else:            d += 4 * (x0 - y0) + 10            y0 -= 1        x0 += 1
在中心圆填充这里，可以取个巧，把几个顶点直接用画线的算法一行一行填充上去。就可以实现下面的效果。代码如下
# 画实心圆def draw_circle_fill(x0, y0, r):    x = 0    y = r    d = 3 - 2 * r    while x <= y:        time.sleep(0.01)        bresenham(x0 + x, y0 + y, x0 - x, y0 + y)        time.sleep(0.01)        bresenham(x0 + x, y0 - y, x0 - x, y0 - y)        time.sleep(0.01)        bresenham(x0 + y, y0 + x, x0 - y, y0 + x)        time.sleep(0.01)        bresenham(x0 + y, y0 - x, x0 - y, y0 - x)        if d < 0:            d += 4 * x + 6        else:            d += 4 * (x - y) + 10            y -= 1        x += 1
扫描线填充
扫描线填充的算法就比较难实现了，需要找到起始的种子，还有每行的种子，因为我这里仅仅用顶点实现起来过于复杂，就索性偷懒用了数组。下面的算法实现部分仅供参考，具体的实现包括种子的选择等等，可以更好一些。
maps = [[0 for x in range(0,400)] for x in range(0,400)]for i in range(200,300):    maps[i][200] = 1    maps[200][i] = 1    maps[i][300] = 1    maps[300][i] = 1for i in range(230,270):    maps[i][230] = 1    maps[i][270] = 1    maps[230][i] = 1    maps[270][i] = 1# 扫描填充mapsdef scan_fill():    seed = (271,296)    stack = []    stack.append(seed)    while len(stack) > 0:        (x,y) = stack.pop()        # 如果已经被填充过，则跳过        if(maps[x][y] == 1):            continue        # 横向填充并记录lx rx        i=0        time.sleep(0.01)        while(maps[x+i][y] == 0):            maps[x+i][y] = 1            win32gui.SetPixel(dc, x+i, y, 0xffffff)            i += 1        rx = x+i-1        i=1        while(maps[x-i][y] == 0):            maps[x-i][y] = 1            win32gui.SetPixel(dc, x-i, y, 0xffffff)            i+=1        lx = x-i+1        # 下一个种子        if y+1>=300:            continue        i=0        while(maps[lx+i][y+1] == 0):            if(maps[lx+i+1][y+1]==1):                stack.append((lx+i,y+1))                break            i+=1        i=0        while(maps[rx-i][y+1] == 0):            if(maps[rx-i-1][y+1]==1):                stack.append((rx-i,y+1))                break            i+=1        if y-1<=0:            continue        i=0        while(maps[lx+i][y-1] == 0):            if(maps[lx+i+1][y-1]==1):                stack.append((lx+i,y-1))                break            i+=1        i=0        while(maps[rx-i][y-1] == 0):            if(maps[rx-i-1][y-1]==1):                stack.append((rx-i,y-1))                break            i+=1scan_fill()
这里是所有代码
上面的代码都是剪切过的，完整的代码如下所示，运行后大家就可以在显示器上看到运行过程：
import timeimport win32guidc = win32gui.GetDC(0)maps = [[0 for x in range(0,400)] for x in range(0,400)]for i in range(200,300):    maps[i][200] = 1    maps[200][i] = 1    maps[i][300] = 1    maps[300][i] = 1for i in range(230,270):    maps[i][230] = 1    maps[i][270] = 1    maps[230][i] = 1    maps[270][i] = 1# 中点算法画圆def draw_circle(x, y, r):    x0 = 0    y0 = r    d = 3 - 2 * r    while x0 <= y0:        time.sleep(0.01)        win32gui.SetPixel(dc, x + x0, y + y0, 0xffffff)        time.sleep(0.01)        win32gui.SetPixel(dc, x + y0, y + x0, 0xffffff)        time.sleep(0.01)        win32gui.SetPixel(dc, x - y0, y + x0, 0xffffff)        time.sleep(0.01)        win32gui.SetPixel(dc, x - x0, y + y0, 0xffffff)        time.sleep(0.01)        win32gui.SetPixel(dc, x - x0, y - y0, 0xffffff)        time.sleep(0.01)        win32gui.SetPixel(dc, x - y0, y - x0, 0xffffff)        time.sleep(0.01)        win32gui.SetPixel(dc, x + y0, y - x0, 0xffffff)        time.sleep(0.01)        win32gui.SetPixel(dc, x + x0, y - y0, 0xffffff)        if d < 0:            d += 4 * x0 + 6        else:            d += 4 * (x0 - y0) + 10            y0 -= 1        x0 += 1# 画线def bresenham(x0, y0, x1, y1):    dx = abs(x1 - x0)    dy = abs(y1 - y0)    sx = 1 if x0 < x1 else -1    sy = 1 if y0 < y1 else -1    err = dx - dy    while True:        #time.sleep(0.01)        win32gui.SetPixel(dc, x0, y0, 0xffffff)        if x0 == x1 and y0 == y1:            break        e2 = 2 * err        if e2 > -dy:            err -= dy            x0 += sx        if e2 < dx:            err += dx            y0 += sy# 画实心圆def draw_circle_fill(x0, y0, r):    x = 0    y = r    d = 3 - 2 * r    while x <= y:        time.sleep(0.01)        bresenham(x0 + x, y0 + y, x0 - x, y0 + y)        time.sleep(0.01)        bresenham(x0 + x, y0 - y, x0 - x, y0 - y)        time.sleep(0.01)        bresenham(x0 + y, y0 + x, x0 - y, y0 + x)        time.sleep(0.01)        bresenham(x0 + y, y0 - x, x0 - y, y0 - x)        if d < 0:            d += 4 * x + 6        else:            d += 4 * (x - y) + 10            y -= 1        x += 1# 画多边形def draw_polygon(points):    for i in range(len(points)):        x0 = points[i][0]        y0 = points[i][1]        x1 = points[(i + 1) % len(points)][0]        y1 = points[(i + 1) % len(points)][1]        bresenham(x0, y0, x1, y1)# 画椭圆def draw_ellipse(x0, y0, a, b):    x = 0    y = b    a2 = a * a    b2 = b * b    d = b2 - a2 * b + a2 / 4    while b2 * x <= a2 * y:        win32gui.SetPixel(dc, x0 + x, y0 + y, 0xffffff)        win32gui.SetPixel(dc, x0 - x, y0 + y, 0xffffff)        win32gui.SetPixel(dc, x0 + x, y0 - y, 0xffffff)        win32gui.SetPixel(dc, x0 - x, y0 - y, 0xffffff)        if d < 0:            d += b2 * (2 * x + 3)        else:            d += b2 * (2 * x - 2 * y + 5)            y -= 1        x += 1    d1 = b2 * (x + 0.5) * (x + 0.5) + a2 * (y - 1) * (y - 1) - a2 * b2    while y >= 0:        win32gui.SetPixel(dc, x0 + x, y0 + y, 0xffffff)        win32gui.SetPixel(dc, x0 - x, y0 + y, 0xffffff)        win32gui.SetPixel(dc, x0 + x, y0 - y, 0xffffff)        win32gui.SetPixel(dc, x0 - x, y0 - y, 0xffffff)        if d1 > 0:            d1 -= a2 * (2 * y - 1)        d1 += b2 * (2 * x + 3)        x += 1        y -= 1# 画矩形def draw_rectangle(x0, y0, x1, y1):    bresenham(x0, y0, x1, y0)    bresenham(x1, y0, x1, y1)    bresenham(x1, y1, x0, y1)    bresenham(x0, y1, x0, y0)# 扫描填充mapsdef scan_fill():    seed = (271,296)    stack = []    stack.append(seed)    while len(stack) > 0:        (x,y) = stack.pop()        # 如果已经被填充过，则跳过        if(maps[x][y] == 1):            continue        # 横向填充并记录lx rx        i=0        time.sleep(0.01)        while(maps[x+i][y] == 0):            maps[x+i][y] = 1            win32gui.SetPixel(dc, x+i, y, 0xffffff)            i += 1        rx = x+i-1        i=1        while(maps[x-i][y] == 0):            maps[x-i][y] = 1                        win32gui.SetPixel(dc, x-i, y, 0xffffff)            i+=1        lx = x-i+1        # 下一个种子        if y+1>=300:            continue        i=0        while(maps[lx+i][y+1] == 0):            if(maps[lx+i+1][y+1]==1):                stack.append((lx+i,y+1))                break            i+=1        i=0        while(maps[rx-i][y+1] == 0):            if(maps[rx-i-1][y+1]==1):                stack.append((rx-i,y+1))                break            i+=1        if y-1<=0:            continue        i=0        while(maps[lx+i][y-1] == 0):            if(maps[lx+i+1][y-1]==1):                stack.append((lx+i,y-1))                break            i+=1        i=0        while(maps[rx-i][y-1] == 0):            if(maps[rx-i-1][y-1]==1):                stack.append((rx-i,y-1))                break            i+=1scan_fill()while True:    # 画线        bresenham(400, 900, 1000, 700)    # 填充圆    draw_circle_fill(900, 500, 100)    # 中心圆    draw_circle(1000, 200, 100)    # 椭圆    draw_ellipse(1500, 200, 100, 100)    # 矩形    draw_rectangle(1100, 400, 1200, 500)    # 多边形    draw_polygon([(900, 1000), (800, 800), (1000, 900), (1100, 1000)])    #三角形    draw_polygon([(400, 200), (500, 300), (600, 200)])
裁剪
裁剪这里简直就是我的噩梦，因为我之前为了极客选择了仅仅知道顶点就画出裁剪过的多边形，导致我没有数组，只能设计更极客的算法。
最后我找到了一种裁剪凸多边形的办法，大致就是找到每个线段的交点，然后顺时针方向对交点和在主多边形，副多边形的顶点排序，最后就可以实现裁剪。代码超级复杂，
import win32guiimport mathimport pygamedc = win32gui.GetDC(0)# 获取鼠标的位置mouse_x=win32gui.GetCursorPos()[0]mouse_y=win32gui.GetCursorPos()[1]temp = win32gui.GetCursorPos()def get_mouse_pos():    global mouse_x, mouse_y    mouse_x = win32gui.GetCursorPos()[0]    mouse_y = win32gui.GetCursorPos()[1]clock = pygame.time.Clock()temp2 = []def bresenham(x0, y0, x1, y1 , color):    dx = abs(x1 - x0)    dy = abs(y1 - y0)    sx = 1 if x0 < x1 else -1    sy = 1 if y0 < y1 else -1    err = dx - dy    while True:        win32gui.SetPixel(dc, x0, y0, color)        if x0 == x1 and y0 == y1:            break        e2 = 2 * err        if e2 > -dy:            err -= dy            x0 += sx        if e2 < dx:            err += dx            y0 += sydef draw_rectangle(x0, y0, x1, y1):    bresenham(x0, y0, x1, y0,0xffffff)    bresenham(x1, y0, x1, y1,0xffffff)    bresenham(x1, y1, x0, y1,0xffffff)    bresenham(x0, y1, x0, y0,0xffffff)def draw_polygon(points):    for i in range(len(points)):        x0 = points[i][0]        y0 = points[i][1]        x1 = points[(i + 1) % len(points)][0]        y1 = points[(i + 1) % len(points)][1]        bresenham(x0, y0, x1, y1,0x00ff00)def draw_polygon_black(points):    for i in range(len(points)):        x0 = points[i][0]        y0 = points[i][1]        x1 = points[(i + 1) % len(points)][0]        y1 = points[(i + 1) % len(points)][1]        bresenham(x0, y0, x1, y1,0x000000)# 线段是否相交def IsRectCross(p1x, p1y, p2x, p2y, q1x, q1y, q2x, q2y):    return min(p1x,p2x) <= max(q1x,q2x) and min(q1x,q2x) <= max(p1x,p2x) and min(p1y,p2y) <= max(q1y,q2y) and min(q1y,q2y) <= max(p1y,p2y)def IsLineSegmentCross(pFirst1x,pFirst1y,pFirst2x,pFirst2y,pSecond1x,pSecond1y,pSecond2x,pSecond2y):    line1 = pFirst1x * (pSecond1y - pFirst2y) + pFirst2x * (pFirst1y - pSecond1y) + pSecond1x * (pFirst2y - pFirst1y)    line2 = pFirst1x * (pSecond2y - pFirst2y) + pFirst2x * (pFirst1y - pSecond2y) + pSecond2x * (pFirst2y - pFirst1y)    if (((line1 ^ line2) >= 0) and not (line1 == 0 and line2 == 0)):        return False    line1 = pSecond1x * (pFirst1y - pSecond2y) + pSecond2x * (pSecond1y - pFirst1y) + pFirst1x * (pSecond2y - pSecond1y)    line2 = pSecond1x * (pFirst2y - pSecond2y) + pSecond2x * (pSecond1y - pFirst2y) + pFirst2x * (pSecond2y - pSecond1y)    if (((line1 ^ line2) >= 0) and not (line1 == 0 and line2 == 0)):        return False    return Truedef GetCrossPoint(p1x, p1y, p2x, p2y, q1x, q1y, q2x, q2y):    if(IsRectCross(p1x, p1y, p2x, p2y, q1x, q1y, q2x, q2y)):        if (IsLineSegmentCross(p1x, p1y, p2x, p2y, q1x, q1y, q2x, q2y)):            tmpLeft = (q2x - q1x) * (p1y - p2y) - (p2x - p1x) * (q1y - q2y)            tmpRight = (p1y - q1y) * (p2x - p1x) * (q2x - q1x) + q1x * (q2y - q1y) * (p2x - p1x) - p1x * (p2y - p1y) * (q2x - q1x)            if (tmpLeft == 0):                return None            x = (int)(tmpRight/tmpLeft)            tmpLeft = (p1x - p2x) * (q2y - q1y) - (p2y - p1y) * (q1x - q2x)            tmpRight = p2y * (p1x - p2x) * (q2y - q1y) + (q2x- p2x) * (q2y - q1y) * (p1y - p2y) - q2y * (q1x - q2x) * (p2y - p1y)            if (tmpLeft == 0):                return None            y = (int)(tmpRight/tmpLeft)            return (x,y)        else:            return None    else:        return Nonedef draw_rectangle_black(x0, y0, x1, y1):    bresenham(x0, y0, x1, y0,0x000000)    bresenham(x1, y0, x1, y1,0x000000)    bresenham(x1, y1, x0, y1,0x000000)    bresenham(x0, y1, x0, y0,0x000000)# 判断点是否在多边形内def IsPointInPolygon(points, x, y):    nCross = 0    for i in range(len(points)):        p1x = points[i][0]        p1y = points[i][1]        p2x = points[(i + 1) % len(points)][0]        p2y = points[(i + 1) % len(points)][1]        if (y > min(p1y, p2y)):            if (y <= max(p1y, p2y)):                if (x <= max(p1x, p2x)):                    if (p1y != p2y):                        xinters = (y - p1y) * (p2x - p1x) / (p2y - p1y) + p1x                    if (p1x == p2x or x <= xinters):                        nCross += 1    if (nCross % 2 == 0):        return False    else:        return Truedef getNonRepeatList(data):    new_data = []    for i in range(len(data)):        if data[i] not in new_data:            new_data.append(data[i])    return new_data# 判断两多边形重叠部分 返回一个多边形def IsPolygonCross(points1, points2):    result = []    for i in range(len(points1)):        p1x = points1[i][0]        p1y = points1[i][1]        p2x = points1[(i + 1) % len(points1)][0]        p2y = points1[(i + 1) % len(points1)][1]        for j in range(len(points2)):            q1x = points2[j][0]            q1y = points2[j][1]            q2x = points2[(j + 1) % len(points2)][0]            q2y = points2[(j + 1) % len(points2)][1]            if (IsPointInPolygon(points1, q1x, q1y) and (q1x, q1y) not in result):                result.append((q1x, q1y))            if (IsPointInPolygon(points1, q2x, q2y) and (q2x, q2y) not in result):                result.append((q2x, q2y))            if (IsPointInPolygon(points2, p1x, p1y) and (p1x, p1y) not in result):                result.append((p1x, p1y))            if (IsPointInPolygon(points2, p2x, p2y) and (p2x, p2y) not in result):                result.append((p2x, p2y))            if (IsRectCross(p1x, p1y, p2x, p2y, q1x, q1y, q2x, q2y)):                if  GetCrossPoint(p1x, p1y, p2x, p2y, q1x, q1y, q2x, q2y) != None:                    (x, y) = GetCrossPoint(p1x, p1y, p2x, p2y, q1x, q1y, q2x, q2y)                    result.append((x, y))    if (result == []):        return result    return (sort_points_in_clockwise_order(result))w = 60h = 100def draw_polygon_red(points):    for i in range(len(points)):        x0 = points[i][0]        y0 = points[i][1]        x1 = points[(i + 1) % len(points)][0]        y1 = points[(i + 1) % len(points)][1]        bresenham(x0, y0, x1, y1,0xff0000)def sort_points_in_clockwise_order(points):    center = (0, 0)    for point in points:        center = (center[0] + point[0], center[1] + point[1])    center = (center[0] / len(points), center[1] / len(points))    points_copy = list(points)    points_copy.sort(key=lambda point: math.atan2(point[0] - center[0], point[1] - center[1]))    res = []    for i in points_copy:       res.append((i[0]+500,i[1]))    return respolygon_Points = [(600,500), (800,500), (900, 600), (900, 400),(600,300)]while True:    draw_rectangle_black(temp[0],temp[1],temp[0]+w,temp[1]+h)    draw_rectangle(mouse_x,mouse_y,mouse_x+w,mouse_y+h)    temp = (mouse_x,mouse_y)    get_mouse_pos()    draw_polygon(polygon_Points)    res =  IsPolygonCross(polygon_Points,[(mouse_x,mouse_y),(mouse_x+w,mouse_y),(mouse_x+w,mouse_y+h),(mouse_x,mouse_y+h)])     print(res)    if temp2 != []:        draw_polygon_black(temp2)    if res != [] and res != None:        draw_polygon_red(res)        temp2 = res    clock.tick(120)# 60帧
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