Pygame 简明教程
Pygame - Transforming Images
pygame.ransform 模块包含许多用于处理从图像或文本块中获得的 Surface 对象的函数的定义。对曲面的处理包括翻转、旋转、缩放、调整大小和缩放对象。
The pygame.ransform module contains definitions of a number of functions for manipulation of Surface objects obtained out of image or text blocks. Manipulation of a surface include flipping, rotation, scaling, resizing and zooming the object.
在 pygame.transform 模块中找到了以下函数。
Following functions are found in pygame.transform module.
flip() |
flip vertically and horizontally |
scale() |
resize to new resolution |
rotate() |
rotate an image |
rotozoom() |
filtered scale and rotation |
scale2x() |
specialized image doubler |
smoothscale() |
scale a surface to an arbitrary size smoothly |
get_smoothscale_backend() |
return smoothscale filter version in use - 'GENERIC', 'MMX', or 'SSE' |
set_smoothscale_backend() |
set smoothscale filter version to one of - 'GENERIC', 'MMX', or 'SSE' |
chop() |
gets a copy of an image with an interior area removed |
laplacian() |
find edges in a surface |
average_surfaces() |
find the average surface from many surfaces. |
average_color() |
finds the average color of a surface |
threshold() |
finds which, and how many pixels in a surface are within a threshold of a 'search_color' or a 'search_surf'. |
让我们首先使用语法如下所示的 flip() 函数：
Let us first use the flip() function whose syntax is as follows −
flip(Surface, xbool, ybool)此函数可以水平、垂直或同时翻转曲面对象。方向由两个 bool 参数决定。
This function can flip the surface object either horizontally, vertically or both. The orientation is decided by two bool parameters.
要水平翻转图像，请使用以下命令：
To flip the image horizontally, use the following command −
pygame.transform.flip(img2,True, False)要垂直翻转，请使用以下命令：
To flip vertically, use the following command −
pygame.transform.flip(img2,False, True)在下面的示例中，pygame徽标图像正常显示并向两个方向翻转。首先从原始图像对象获得翻转的表面，获取其矩形对象，然后构建它。为了水平翻转图像，
In the following example, pygame logo image is displayed normally and flipping in both directions. First obtained flipped surface from original image object, fetch its Rect object and then built it. To render horizontally flipped image,
img1 = pygame.image.load('pygame.png')
img2=img1
img2=pygame.transform.flip(img2,True, False)
#inside event loop
rect2 = img2.get_rect()
rect2.center = 200, 150
screen.blit(img2, rect2)Example
渲染原始的Pygame徽标及其翻转图像的完整代码如下所示：
The complete code for rendering original Pygame logo and its flipped images is as follows −
import pygame
pygame.init()
screen = pygame.display.set_mode((400, 300))
pygame.display.set_caption("Flip image")
img1 = pygame.image.load('pygame.png')
img2=img1
img3=img1
img2=pygame.transform.flip(img2,True, False)
img3=pygame.transform.flip(img3, False, True)
done = False
bg = (127,127,127)
while not done:
for event in pygame.event.get():
screen.fill(bg)
rect1 = img1.get_rect()
rect1.center = 200, 50
screen.blit(img1, rect1)
rect2 = img2.get_rect()
rect2.center = 200, 150
screen.blit(img2, rect2)
rect3 = img3.get_rect()
rect3.center = 200, 250
screen.blit(img3, rect3)
if event.type == pygame.QUIT:
done = True
pygame.display.update()
Example
负角度值以顺时针方向旋转表面。
Negative value of angle rotates the surface in clockwise direction.
import pygame
pygame.init()
screen = pygame.display.set_mode((400, 300))
pygame.display.set_caption("rotate image")
img1 = pygame.image.load('pygame.png')
img2=img1
img3=img1
img2=pygame.transform.rotate(img2,90)
img3=pygame.transform.rotate(img3, -90)
done = False
bg = (127,127,127)
while not done:
for event in pygame.event.get():
screen.fill(bg)
rect1 = img1.get_rect()
rect1.center = 200, 50
screen.blit(img1, rect1)
rect2 = img2.get_rect()
rect2.center = 100, 200
screen.blit(img2, rect2)
rect3 = img3.get_rect()
rect3.center = 300,200
screen.blit(img3, rect3)
if event.type == pygame.QUIT:
done = True
pygame.display.update()
Example
laplacian()函数提取曲面对象的轮廓。此函数只接受一个参数，图像对象本身。
The laplacian() function extracts outline of the surface object. The function just takes one argument, the image object itself.
import pygame
pygame.init()
screen = pygame.display.set_mode((400, 300))
pygame.display.set_caption("Laplacian of image")
img1 = pygame.image.load('pygame.png')
img2=img1
img2=pygame.transform.laplacian(img2)
done = False
bg = (127,127,127)
while not done:
for event in pygame.event.get():
screen.fill(bg)
rect1 = img1.get_rect()
rect1.center = 200, 50
screen.blit(img1, rect1)
rect2 = img2.get_rect()
rect2.center = 200, 200
screen.blit(img2, rect2)
if event.type == pygame.QUIT:
done = True
pygame.display.update()Output
为了使Surface对象随鼠标移动而移动，从图像中心计算x、y坐标。我们还计算中心到鼠标的距离d。函数atan2(y,x)能找到旋转角度。我们需要把弧度转换成角度。根据鼠标到中心的距离，我们计算出比例参数。
To make the Surface object move along with mouse movement, calculate the x, y coordinates from the center of the image. We also calculate the center-mouse distance d. The atan2(y, x) math function allows to find the rotation angle. We need to transform radians in degrees. From the distance mouse-center we calculate the scale argument.
mouse = event.pos
Pygame
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x = mouse[0] - 200
y = mouse[1] - 150
d = math.sqrt(x ** 2 + y ** 2)
angle = math.degrees(-math.atan2(y, x))
scale = abs(5 * d / 400)最后，我们使用rotzoom()函数执行组合旋转和缩放变换。
Finally, we use rotzoom() function which performs combined rotation and scaling transform.
rotozoom(Surface, angle, scale)Example
下面的代码渲染Pygame徽标图像，可以根据鼠标移动进行旋转。
Following code renders Pygame logo image that can be rotated in accordance with mouse movement.
import pygame , math
from pygame.locals import *
pygame.init()
screen = pygame.display.set_mode((400, 300))
pygame.display.set_caption("Move image with mouse")
img1 = pygame.image.load('pygame.png')
done = False
bg = (127,127,127)
while not done:
for event in pygame.event.get():
screen.fill(bg)
if event.type == pygame.QUIT:
done = True
if event.type == MOUSEMOTION:
mouse = event.pos
x = mouse[0] - 200
y = mouse[1] - 150
d = math.sqrt(x ** 2 + y ** 2)
angle = math.degrees(-math.atan2(y, x))
scale = abs(5 * d / 400)
img2 = pygame.transform.rotozoom(img1, angle, scale)
rect = img2.get_rect()
rect.center = (200,150)
screen.blit(img2, rect)
pygame.display.update()