pygame

Author: furas

pygame/scrolling-image/scrolling-mousemotion/README.md

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+
+author: https://blog.furas.pl
+
+date: 2020.07.16
+
+link: https://stackoverflow.com/questions/62940130/how-to-implement-a-scroll-view-in-pygame/
+
+---
+
+Code moves images when mouse is moved (without clicking button)
+
+`camera_rect` keeps `offset` used to move/positioning image.
+
+Event `MOUSEMOTION` and `event.rel` is used to change value in `camera_rect`.
+
+It was created for image `800x600` and window `400x300` and it moves full image 
+but for different sizes it may need different calculations - 
+or it may need to calculate mouse position as percentage 
+and use this percentage to calculate image position.

pygame/scrolling-image/scrolling-mousemotion/image-800x600.jpg

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+
+# author: https://blog.furas.pl
+# date: 2020.07.16
+# link: https://stackoverflow.com/questions/62940130/how-to-implement-a-scroll-view-in-pygame/
+
+import pygame
+
+# === CONSTANS === (UPPER_CASE names)
+
+#BLACK = (  0,   0,   0)
+#WHITE = (255, 255, 255)
+
+#RED   = (255,   0,   0)
+#GREEN = (  0, 255,   0)
+#BLUE  = (  0,   0, 255)
+
+SCREEN_WIDTH  = 400
+SCREEN_HEIGHT = 300
+
+# === CLASSES === (CamelCase names)
+
+    # empty
+    
+# === FUNCTIONS === (lower_case names)
+
+    # empty
+    
+# === MAIN === (lower_case names)
+
+# --- (global) variables --- 
+
+# --- init ---
+
+pygame.init()
+
+screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))
+screen_rect = screen.get_rect()
+
+# --- objects ---
+
+image = pygame.image.load('image-800x600.jpg')
+image_rect = image.get_rect()
+
+# --- camera / offset ---
+
+camera_rect = screen_rect.copy()
+
+# --- mainloop ---
+
+#button_pressed = False
+
+clock = pygame.time.Clock()
+is_running = True
+
+while is_running:
+
+    # --- events ---
+    
+    for event in pygame.event.get():
+
+        # --- global events ---
+        
+        if event.type == pygame.QUIT:
+            is_running = False
+            
+        elif event.type == pygame.KEYDOWN:
+            if event.key == pygame.K_ESCAPE:
+                is_running = False
+
+        #elif event.type == pygame.MOUSEBUTTONDOWN:
+        #    button_pressed = True
+        #elif event.type == pygame.MOUSEBUTTONUP:
+        #    button_pressed = False
+
+        elif event.type == pygame.MOUSEMOTION:
+            #if button_pressed:
+    
+                camera_rect.x += event.rel[0]
+                # check left/right limit
+                if camera_rect.left < image_rect.left:
+                    camera_rect.left = image_rect.left
+                if camera_rect.right > image_rect.right:
+                    camera_rect.right = image_rect.right
+    
+                camera_rect.y += event.rel[1]
+                # check up/down limit
+                if camera_rect.top < image_rect.top:
+                    camera_rect.top = image_rect.top
+                if camera_rect.bottom > image_rect.bottom:
+                    camera_rect.bottom = image_rect.bottom
+                    
+        # --- objects events ---
+
+    # --- updates ---
+
+        
+    # --- draws ---
+    
+    #screen.fill(BLACK)
+
+    # draw image
+    screen.blit(image, (-camera_rect.x, -camera_rect.y))
+    #screen.blit(image, camera_rect)
+
+    pygame.display.update()
+
+    # --- FPS ---
+
+    clock.tick(25)
+
+# --- the end ---
+    
+pygame.quit()
+

pygame/scrolling-image/scrolling-mousemotion/main-1.py

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+
+# author: https://blog.furas.pl
+# date: 2020.07.16
+# link: https://stackoverflow.com/questions/62940130/how-to-implement-a-scroll-view-in-pygame/
+
+import pygame
+
+# === CONSTANS === (UPPER_CASE names)
+
+#BLACK = (  0,   0,   0)
+#WHITE = (255, 255, 255)
+
+#RED   = (255,   0,   0)
+#GREEN = (  0, 255,   0)
+#BLUE  = (  0,   0, 255)
+
+SCREEN_WIDTH  = 400
+SCREEN_HEIGHT = 600
+
+# === CLASSES === (CamelCase names)
+
+# empty
+    
+# === FUNCTIONS === (lower_case names)
+
+# empty
+    
+# === MAIN === (lower_case names)
+
+# --- (global) variables --- 
+
+# --- init ---
+
+pygame.init()
+
+screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))
+screen_rect = screen.get_rect()
+
+# --- objects ---
+
+image = pygame.image.load('image-800x600.jpg')
+image_rect = image.get_rect()
+
+# --- camera / offset ---
+
+camera_rect = screen_rect.copy()
+
+percentage_x = 0
+percentage_y = 0
+
+# --- mainloop ---
+
+#button_pressed = False
+
+clock = pygame.time.Clock()
+is_running = True
+
+while is_running:
+
+    # --- events ---
+    
+    for event in pygame.event.get():
+
+        # --- global events ---
+        
+        if event.type == pygame.QUIT:
+            is_running = False
+            
+        elif event.type == pygame.KEYDOWN:
+            if event.key == pygame.K_ESCAPE:
+                is_running = False
+
+        elif event.type == pygame.MOUSEMOTION:
+            percentage_x = event.pos[0] / screen_rect.width
+            camera_rect.x = percentage_x * (image_rect.width - screen_rect.width)
+
+            #percentage_y = event.pos[1] / screen_rect.height
+            #camera_rect.y = percentage_y * (image_rect.height - screen_rect.height)
+                    
+        # --- objects events ---
+        
+        # empty
+        
+    # --- updates ---
+
+    # empty
+        
+    # --- draws ---
+    
+    #screen.fill(BLACK)
+
+    # draw image
+    screen.blit(image, (-camera_rect.x, -camera_rect.y))
+    #screen.blit(image, camera_rect)
+
+    pygame.display.update()
+
+    # --- FPS ---
+
+    clock.tick(25)
+
+# --- the end ---
+    
+pygame.quit()
+