initial commit

README.md

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+# PatljaPg - make simple PyGame examples even simpler
+
+PetljaPg is a small Python module intented to reduce boilerplate code in entry level PyGame programming.
+
+Design principles of PetljaPg:
+
+- PegljaPg should reduce entry barriers for PyGame learners
+- PetljaPg should let a coder to code in PyGame with minimal interference of PetljaPg API
+- PetljaPg can be easily dropped somewhere on a PyGame learning path
+- PetljaPg need not provide any value to non-beginner developers
+
+
+Initial focus areas of PetljaPg are:
+- hide complexity of the main loop
+- optionaly hide the initialization code
+- enabe some user interaction with reduced complexity of event handling

petljapg.py

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+import pygame as pg
+
+class pg_frame:
+    def __init__(self, rate, seq, surf):
+        self.sequence = seq
+        self.events = []
+        self.rate = rate
+        self.period = 1 / rate
+        self.surface = surf
+        self._mouse_left_index = 0
+        self.mouse_pos = None
+
+
+
+    def _key_count(self, key):
+        cnt = 0
+        for e in self.events:
+            if e.type == pg.KEYDOWN and e.key == key:
+                cnt += 1
+        return cnt
+
+    def key_left_count(self):
+        return self._key_count(pg.K_LEFT)
+
+    def key_right_count(self):
+        return self._key_count(pg.K_RIGHT)
+
+    def key_up_count(self):
+        return self._key_count(pg.K_UP)
+
+    def key_down_count(self):
+        return self._key_count(pg.K_DOWN)
+
+    def key_space_count(self):
+        return self._key_count(pg.K_SPACE)
+
+    def mouse_left_clicked(self):
+        while (self._mouse_left_index < len(self.events) and 
+                self.events[self._mouse_left_index].type != pg.MOUSEBUTTONDOWN):
+            self._mouse_left_index += 1
+        if self._mouse_left_index < len(self.events):
+            e = self.events[self._mouse_left_index]
+            self.mouse_pos = e.pos
+            self._mouse_left_index += 1
+            return True
+        else:
+            return None
+
+
+
+
+def frames(rate, size=None, caption=None):
+    if pg.get_init():
+        if size is not None:
+            raise ValueError("Argument 'size' is not expected when pygame is allready initialized")
+        if caption is not None:
+            raise ValueError("Argument 'caption' is not expected when pygame is allready initialized")
+        surf = None
+        manage_init = False
+    else:
+        pg.init()
+        if size is not None:
+            surf = pg.display.set_mode(size)
+        else:
+            surf = pg.display.set_mode((500,500))
+        if caption is not None:
+            pg.display.set_caption(caption)
+        pg.key.set_repeat(500, 10)  
+        manage_init = True
+
+    sat = pg.time.Clock() 
+    kraj = False
+    seq = 0
+    while not kraj:
+        frm = pg_frame(rate, seq, surf)
+        seq += 1
+        for dogadjaj in pg.event.get():    
+            if dogadjaj.type == pg.QUIT:   
+                kraj = True
+            else:
+                frm.events.append(dogadjaj)    
+        yield frm
+        pg.display.update() 
+        sat.tick(rate) 
+    if manage_init:
+        pg.quit()  

primer0.py

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+import pygame as pg
+import petljapg
+
+tri_boje = [pg.Color("red"), pg.Color("yellow"), pg.Color("green")]
+
+for frm in petljapg.frames(rate=1, size=(400,400)):
+    boja = tri_boje[frm.sequence % 3]
+    pg.draw.circle(frm.surface, boja, (200,200), 100)

primer1.py

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+import pygame as pg
+import petljapg
+
+x = 150
+y = 150
+
+for frm in petljapg.frames(rate=30, size=(500,300)):
+    platno = frm.surface
+    platno.fill(pg.Color("white"))
+    x = x + frm.key_right_count() - frm.key_left_count()
+    y = y + frm.key_down_count() - frm.key_up_count()
+    boja = pg.Color("red")
+    pg.draw.circle(platno, boja, (x, y), 30)
+

primer1a.py

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+import pygame as pg
+import petljapg
+
+pg.init()  # inicijalizujemo rad biblioteke PyGame
+pg.display.set_caption("Хватање јабука")  # otvaramo prozor
+(sirina, visina) = (500, 300)
+platno = pg.display.set_mode((sirina, visina))
+
+pg.key.set_repeat(10, 10)  # podešavamo dogadjaje tastature
+
+x = 150
+y = 150
+
+# pygame je vec inicijalizovan
+for frm in petljapg.frames(rate=30):
+    platno.fill(pg.Color("white"))
+    x = x + frm.key_right_count() - frm.key_left_count()
+    y = y + frm.key_down_count() - frm.key_up_count()
+    boja = pg.Color("red")
+    pg.draw.circle(platno, boja, (x, y), 30)
+
+# ako se ne managuje init u frames(), ne manageuje se ni quit
+pg.quit()

primer2.py

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+import pygame as pg
+import petljapg
+
+x = 150
+y = 150
+
+tri_boje = [pg.Color("red"), pg.Color("yellow"), pg.Color("green")]
+izbor_boje = 0
+
+# u elementarnim primerima ne insistiramo na podeli ažuriranja stanja i crtanja
+# u nekom trenutku ćemo izvući crtanje u posebnu funkciju
+for frm in petljapg.frames(rate=30, size=(500,300)):
+    platno = frm.surface
+    platno.fill(pg.Color("black"))
+    x = x + frm.key_right_count() - frm.key_left_count()
+    y = y + frm.key_down_count() - frm.key_up_count()
+    izbor_boje = (izbor_boje + frm.key_space_count()) % 3
+    boja = tri_boje[izbor_boje]
+    pg.draw.circle(platno, boja, (x, y), 30)
+

primer3.py

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+import pygame as pg
+import petljapg
+
+
+x = 150
+y = 150
+vx = 0
+vy = 0
+
+# crtanje možemo lako odvojiti u posebnu funkciju, ali na to
+# možemo da pređemo kada nam bude zaista zatrebalo, ne moramo
+# od početka
+
+def crtaj(platno):
+    platno.fill(pg.Color("white"))
+    boja = pg.Color("red")
+    pg.draw.circle(platno, boja, (int(x), int(y)), 30)
+
+for frm in petljapg.frames(rate=30, size=(500,300)):
+    sirina, visina = frm.surface.get_size()
+
+    vx = vx + frm.key_right_count() - frm.key_left_count()
+    x = (x + vx * frm.period) % sirina
+
+    vy = vy + frm.key_down_count() - frm.key_up_count()
+    y = (y + vy * frm.period) % visina
+
+    crtaj(frm.surface)

primer4.py

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+import pygame as pg
+import petljapg
+
+x = 150
+y = 150
+
+#Evo kako bismo mogli da pojednostavimo reagovanje na klika miša
+for frm in petljapg.frames(rate=30, size=(500,300)):
+    platno = frm.surface
+    platno.fill(pg.Color("white"))
+    if frm.mouse_left_clicked():
+        x, y = frm.mouse_pos
+    pg.draw.circle(platno, pg.Color("blue"), (x, y), 50)
+