I converted a simple text box input taking method to some modern python implementation
case 8: // if backspace is pressed delete the last character from str
if(kbhit()) key[0]=getch();// get the character typed if any before the loop starts
if(keycount>18) // If key count greater than 18 stop taking input
"""
A small, reusable text box widget for pygame 2.
pip install pygame
python textbox.py
Click the box to focus it. Enter submits, Esc quits.
Supports: insertion at the cursor, Backspace/Delete, Left/Right/Home/End,
click-to-position, key repeat, max length, placeholder and horizontal scrolling.
"""
import pygame
BG = (30, 30, 36)
BOX_IDLE = (70, 70, 80)
BOX_ACTIVE = (90, 160, 255)
TEXT = (235, 235, 240)
HINT = (120, 120, 130)
BLINK_MS = 500 # cursor is visible for 500 ms, hidden for 500 ms
class TextBox:
PAD = 8
def __init__(self, rect, font, max_length=20, placeholder=""):
self.rect = pygame.Rect(rect)
self.font = font
self.max_length = max_length
self.placeholder = placeholder
self.text = ""
self.cursor = 0 # index in self.text where the caret sits
self.active = False
self._scroll = 0 # horizontal pixel offset of the text
self._blink_start = pygame.time.get_ticks()
# ---------- helpers ----------
def _touch(self):
"""Restart the blink cycle so the caret is visible right after input."""
self._blink_start = pygame.time.get_ticks()
def _caret_x(self):
return self.font.size(self.text[: self.cursor])[0]
def _update_scroll(self):
"""Keep the caret inside the visible area."""
visible = self.rect.width - 2 * self.PAD
caret = self._caret_x()
if caret - self._scroll > visible:
self._scroll = caret - visible
elif caret - self._scroll < 0:
self._scroll = caret
self._scroll = max(0, self._scroll)
def _index_at(self, mouse_x):
"""Character index nearest to a mouse x position."""
x = mouse_x - self.rect.x - self.PAD + self._scroll
best, best_dist = 0, float("inf")
for i in range(len(self.text) + 1):
dist = abs(self.font.size(self.text[:i])[0] - x)
if dist < best_dist:
best, best_dist = i, dist
return best
# ---------- events ----------
def handle_event(self, event):
"""Feed every pygame event here. Returns the text when Enter is pressed."""
if event.type == pygame.MOUSEBUTTONDOWN and event.button == 1:
self.active = self.rect.collidepoint(event.pos)
if self.active:
self.cursor = self._index_at(event.pos[0])
self._touch()
return None
if not self.active:
return None
if event.type == pygame.TEXTINPUT:
# TEXTINPUT already handles shift, layouts and IMEs correctly.
chunk = "".join(c for c in event.text if c.isprintable())
chunk = chunk[: self.max_length - len(self.text)]
if chunk:
self.text = self.text[: self.cursor] + chunk + self.text[self.cursor:]
self.cursor += len(chunk)
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_BACKSPACE and self.cursor > 0:
self.text = self.text[: self.cursor - 1] + self.text[self.cursor:]
self.cursor -= 1
elif event.key == pygame.K_DELETE:
self.text = self.text[: self.cursor] + self.text[self.cursor + 1:]
elif event.key == pygame.K_LEFT:
self.cursor = max(0, self.cursor - 1)
elif event.key == pygame.K_RIGHT:
self.cursor = min(len(self.text), self.cursor + 1)
elif event.key == pygame.K_HOME:
self.cursor = 0
elif event.key == pygame.K_END:
self.cursor = len(self.text)
elif event.key in (pygame.K_RETURN, pygame.K_KP_ENTER):
return self.text
else:
return None
else:
return None
self._touch()
return None
# ---------- drawing ----------
def draw(self, surface):
pygame.draw.rect(surface, (45, 45, 54), self.rect, border_radius=6)
pygame.draw.rect(surface, BOX_ACTIVE if self.active else BOX_IDLE,
self.rect, width=2, border_radius=6)
self._update_scroll()
inner = self.rect.inflate(-2 * self.PAD, -4)
old_clip = surface.get_clip()
surface.set_clip(inner)
if self.text:
img = self.font.render(self.text, True, TEXT)
else:
img = self.font.render(self.placeholder, True, HINT)
y = self.rect.centery - img.get_height() // 2
surface.blit(img, (inner.x - self._scroll, y))
# Blink using elapsed time, so the main loop never has to sleep.
blink_on = ((pygame.time.get_ticks() - self._blink_start) // BLINK_MS) % 2 == 0
if self.active and blink_on:
cx = inner.x - self._scroll + self._caret_x()
pygame.draw.line(surface, TEXT, (cx, y), (cx, y + img.get_height()), 2)
surface.set_clip(old_clip)
def main():
pygame.init()
screen = pygame.display.set_mode((480, 240))
pygame.display.set_caption("Text box")
font = pygame.font.SysFont("segoeui,arial", 24)
clock = pygame.time.Clock()
box = TextBox((40, 80, 400, 44), font, max_length=20, placeholder="Type here...")
box.active = True
pygame.key.set_repeat(400, 35) # hold a key to repeat it
pygame.key.start_text_input()
submitted = ""
running = True
while running:
for event in pygame.event.get():
if event.type == pygame.QUIT or (
event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE
):
running = False
result = box.handle_event(event)
if result is not None:
submitted = result
screen.fill(BG)
box.draw(screen)
if submitted:
msg = font.render(f"Submitted: {submitted!r} ({len(submitted)} chars)", True, HINT)
screen.blit(msg, (40, 160))
pygame.display.flip()
clock.tick(60)
pygame.quit()
if __name__ == "__main__":
main()
