196 lines
6.6 KiB
Python
196 lines
6.6 KiB
Python
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#!/usr/bin/env python
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"""An zoomed image viewer that demonstrates Surface.scroll
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This example shows a scrollable image that has a zoom factor of eight.
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It uses the Surface.scroll function to shift the image on the display
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surface. A clip rectangle protects a margin area. If called as a function,
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the example accepts an optional image file path. If run as a program
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it takes an optional file path command line argument. If no file
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is provided a default image file is used.
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When running click on a black triangle to move one pixel in the direction
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the triangle points. Or use the arrow keys. Close the window or press ESC
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to quit.
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"""
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import sys
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import os
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import pygame
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from pygame.transform import scale
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from pygame.locals import *
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main_dir = os.path.dirname(os.path.abspath(__file__))
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DIR_UP = 1
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DIR_DOWN = 2
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DIR_LEFT = 3
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DIR_RIGHT = 4
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zoom_factor = 8
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def draw_arrow(surf, color, posn, direction):
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x, y = posn
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if direction == DIR_UP:
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pointlist = ((x - 29, y + 30), (x + 30, y + 30),
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(x + 1, y - 29), (x, y - 29))
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elif direction == DIR_DOWN:
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pointlist = ((x - 29, y - 29), (x + 30, y - 29),
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(x + 1, y + 30), (x, y + 30))
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elif direction == DIR_LEFT:
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pointlist = ((x + 30, y - 29), (x + 30, y + 30),
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(x - 29, y + 1), (x - 29, y))
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else:
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pointlist = ((x - 29, y - 29), (x - 29, y + 30),
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(x + 30, y + 1), (x + 30, y))
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pygame.draw.polygon(surf, color, pointlist)
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def add_arrow_button(screen, regions, posn, direction):
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draw_arrow(screen, Color('black'), posn, direction)
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draw_arrow(regions, (direction, 0, 0), posn, direction)
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def scroll_view(screen, image, direction, view_rect):
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dx = dy = 0
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src_rect = None
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zoom_view_rect = screen.get_clip()
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image_w, image_h = image.get_size()
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if direction == DIR_UP:
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if view_rect.top > 0:
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screen.scroll(dy=zoom_factor)
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view_rect.move_ip(0, -1)
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src_rect = view_rect.copy()
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src_rect.h = 1
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dst_rect = zoom_view_rect.copy()
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dst_rect.h = zoom_factor
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elif direction == DIR_DOWN:
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if view_rect.bottom < image_h:
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screen.scroll(dy=-zoom_factor)
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view_rect.move_ip(0, 1)
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src_rect = view_rect.copy()
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src_rect.h = 1
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src_rect.bottom = view_rect.bottom
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dst_rect = zoom_view_rect.copy()
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dst_rect.h = zoom_factor
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dst_rect.bottom = zoom_view_rect.bottom
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elif direction == DIR_LEFT:
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if view_rect.left > 0:
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screen.scroll(dx=zoom_factor)
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view_rect.move_ip(-1, 0)
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src_rect = view_rect.copy()
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src_rect.w = 1
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dst_rect = zoom_view_rect.copy()
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dst_rect.w = zoom_factor
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elif direction == DIR_RIGHT:
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if view_rect.right < image_w:
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screen.scroll(dx=-zoom_factor)
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view_rect.move_ip(1, 0)
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src_rect = view_rect.copy()
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src_rect.w = 1
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src_rect.right = view_rect.right
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dst_rect = zoom_view_rect.copy()
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dst_rect.w = zoom_factor
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dst_rect.right = zoom_view_rect.right
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if src_rect is not None:
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scale(image.subsurface(src_rect),
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dst_rect.size,
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screen.subsurface(dst_rect))
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pygame.display.update(zoom_view_rect)
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def main(image_file=None):
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if image_file is None:
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image_file = os.path.join(main_dir, 'data', 'arraydemo.bmp')
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margin = 80
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view_size = (30, 20)
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zoom_view_size = (view_size[0] * zoom_factor,
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view_size[1] * zoom_factor)
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win_size = (zoom_view_size[0] + 2 * margin,
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zoom_view_size[1] + 2 * margin)
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background_color = Color('beige')
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pygame.init()
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# set up key repeating so we can hold down the key to scroll.
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old_k_delay, old_k_interval = pygame.key.get_repeat ()
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pygame.key.set_repeat (500, 30)
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try:
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screen = pygame.display.set_mode(win_size)
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screen.fill(background_color)
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pygame.display.flip()
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image = pygame.image.load(image_file).convert()
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image_w, image_h = image.get_size()
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if image_w < view_size[0] or image_h < view_size[1]:
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print ("The source image is too small for this example.")
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print ("A %i by %i or larger image is required." % zoom_view_size)
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return
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regions = pygame.Surface(win_size, 0, 24)
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add_arrow_button(screen, regions,
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(40, win_size[1] // 2), DIR_LEFT)
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add_arrow_button(screen, regions,
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(win_size[0] - 40, win_size[1] // 2), DIR_RIGHT)
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add_arrow_button(screen, regions,
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(win_size[0] // 2, 40), DIR_UP)
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add_arrow_button(screen, regions,
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(win_size[0] // 2, win_size[1] - 40), DIR_DOWN)
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pygame.display.flip()
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screen.set_clip((margin, margin, zoom_view_size[0], zoom_view_size[1]))
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view_rect = Rect(0, 0, view_size[0], view_size[1])
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scale(image.subsurface(view_rect), zoom_view_size,
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screen.subsurface(screen.get_clip()))
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pygame.display.flip()
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# the direction we will scroll in.
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direction = None
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clock = pygame.time.Clock()
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clock.tick()
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going = True
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while going:
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# wait for events before doing anything.
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#events = [pygame.event.wait()] + pygame.event.get()
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events = pygame.event.get()
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for e in events:
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if e.type == KEYDOWN:
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if e.key == K_ESCAPE:
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going = False
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elif e.key == K_DOWN:
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scroll_view(screen, image, DIR_DOWN, view_rect)
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elif e.key == K_UP:
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scroll_view(screen, image, DIR_UP, view_rect)
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elif e.key == K_LEFT:
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scroll_view(screen, image, DIR_LEFT, view_rect)
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elif e.key == K_RIGHT:
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scroll_view(screen, image, DIR_RIGHT, view_rect)
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elif e.type == QUIT:
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going = False
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elif e.type == MOUSEBUTTONDOWN:
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direction = regions.get_at(e.pos)[0]
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elif e.type == MOUSEBUTTONUP:
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direction = None
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if direction:
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scroll_view(screen, image, direction, view_rect)
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clock.tick(30)
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finally:
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pygame.key.set_repeat (old_k_delay, old_k_interval)
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pygame.quit()
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if __name__ == '__main__':
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if len(sys.argv) > 1:
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image_file = sys.argv[1]
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else:
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image_file = None
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main(image_file)
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