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refactor text display to handle smooth scrolling

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ChuckBuilds
2025-05-26 10:04:44 -05:00
parent bb4ff9cf0c
commit 864b11e1e0
1 changed files with 172 additions and 70 deletions
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242
src/text_display.py
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@@ -21,12 +21,74 @@ class TextDisplay:
self.bg_color = tuple(self.config.get('background_color', [0, 0, 0]))
self.font = self._load_font()
self.text_width = self._calculate_text_width()
self.scroll_pos = 0
self.text_pixel_width = 0 # Authoritative width of the text
self.text_image_cache = None # For pre-rendered text
self._regenerate_renderings() # Initial creation of cache and width calculation
self.scroll_pos = 0.0 # Use float for precision
self.last_update_time = time.time()
self.scroll_speed = self.config.get('scroll_speed', 30) # Pixels per second
def _regenerate_renderings(self):
"""Calculate text width and attempt to create/update the text image cache."""
if not self.text or not self.font:
self.text_pixel_width = 0
self.text_image_cache = None
return
# Always calculate the authoritative text width
try:
self.text_pixel_width = self.display_manager.get_text_width(self.text, self.font)
except Exception as e:
logger.error(f"Error calculating text width: {e}")
self.text_pixel_width = 0
self.text_image_cache = None
return
self._create_text_image_cache()
self.scroll_pos = 0 # Reset scroll position when text changes
def _create_text_image_cache(self):
"""Pre-render the text onto an image if using a TTF font."""
self.text_image_cache = None # Clear previous cache
if not self.text or not self.font or self.text_pixel_width == 0:
return
if isinstance(self.font, freetype.Face):
logger.info("TextDisplay: Pre-rendering cache is not used for BDF/freetype fonts. Will use direct drawing.")
return
# --- TTF Caching Path ---
try:
# Use a dummy image to get accurate text bounding box for vertical centering
dummy_img = Image.new('RGB', (1, 1))
dummy_draw = ImageDraw.Draw(dummy_img)
# Pillow's textbbox gives (left, top, right, bottom) relative to anchor (0,0)
bbox = dummy_draw.textbbox((0, 0), self.text, font=self.font)
actual_text_render_height = bbox[3] - bbox[1] # The actual height of the pixels of the text
# bbox[1] is the y-offset from the drawing point (where text is anchored) to the top of the text.
cache_width = self.text_pixel_width
cache_height = self.display_manager.matrix.height # Cache is always full panel height
self.text_image_cache = Image.new('RGB', (cache_width, cache_height), self.bg_color)
draw_cache = ImageDraw.Draw(self.text_image_cache)
# Calculate y-position to draw the text on the cache for vertical centering.
# The drawing point for PIL's draw.text is typically the baseline.
# y_draw_on_cache = (desired_top_edge_of_text_on_cache) - bbox[1]
desired_top_edge = (cache_height - actual_text_render_height) // 2
y_draw_on_cache = desired_top_edge - bbox[1]
draw_cache.text((0, y_draw_on_cache), self.text, font=self.font, fill=self.text_color)
logger.info(f"TextDisplay: Created text cache for '{self.text[:30]}...' (TTF). Size: {cache_width}x{cache_height}")
except Exception as e:
logger.error(f"TextDisplay: Failed to create text image cache: {e}", exc_info=True)
self.text_image_cache = None
def _load_font(self):
"""Load the specified font file (TTF or BDF)."""
font_path = self.font_path
@@ -72,6 +134,8 @@ class TextDisplay:
def _calculate_text_width(self):
"""Calculate the pixel width of the text with the loaded font."""
try:
# This method is now largely superseded by _regenerate_renderings setting self.text_pixel_width
# Kept for potential direct calls or clarity, but should rely on self.text_pixel_width
return self.display_manager.get_text_width(self.text, self.font)
except Exception as e:
logger.error(f"Error calculating text width: {e}")
@@ -79,87 +143,125 @@ class TextDisplay:
def update(self):
"""Update scroll position if scrolling is enabled."""
if not self.scroll_enabled or self.text_width <= self.display_manager.matrix.width:
self.scroll_pos = 0 # Reset if not scrolling or text fits
if not self.scroll_enabled or self.text_pixel_width <= self.display_manager.matrix.width:
self.scroll_pos = 0.0 # Reset if not scrolling or text fits
return
current_time = time.time()
delta_time = current_time - self.last_update_time
self.last_update_time = current_time
# Calculate scroll distance
scroll_delta = delta_time * self.scroll_speed
self.scroll_pos += scroll_delta
# Reset scroll position when the text has scrolled completely off screen
# Add some padding (e.g., matrix width) before resetting
if self.scroll_pos > self.text_width + self.display_manager.matrix.width:
self.scroll_pos = 0 # Reset to start from the right edge again
# Reset scroll position
if self.text_image_cache: # Using cached image, scroll_pos is offset into cache
# Loop smoothly over the cached image width
if self.scroll_pos >= self.text_pixel_width:
self.scroll_pos %= self.text_pixel_width
else: # Not using cache (e.g., BDF), original scroll logic for off-screen reset
# Reset when text fully scrolled past left edge + matrix width padding (appearance of starting from right)
if self.scroll_pos > self.text_pixel_width + self.display_manager.matrix.width:
self.scroll_pos = 0.0
def display(self):
"""Draw the text onto the display manager's canvas."""
# Explicitly create a new image and draw context for the display manager
self.display_manager.image = Image.new('RGB', (self.display_manager.matrix.width, self.display_manager.matrix.height))
self.display_manager.draw = ImageDraw.Draw(self.display_manager.image)
# Draw the background rectangle first
self.display_manager.draw.rectangle(
(0, 0, self.display_manager.matrix.width, self.display_manager.matrix.height),
fill=self.bg_color
)
matrix_width = self.display_manager.matrix.width
matrix_height = self.display_manager.matrix.height
dm = self.display_manager
matrix_width = dm.matrix.width
matrix_height = dm.matrix.height
# Calculate Y position (center vertically)
# This might need adjustment depending on font metrics
try:
if isinstance(self.font, freetype.Face):
# Estimate height for freetype (BDF)
# Using ascender/descender might be more accurate if available
text_height = self.font.size.height >> 6
# Create a new image and draw context for the display manager for this frame
# Fill with background color. If cache is used, it also has bg color, so this is fine.
dm.image = Image.new('RGB', (matrix_width, matrix_height), self.bg_color)
dm.draw = ImageDraw.Draw(dm.image) # dm.draw needed for fallback path
if not self.text or self.text_pixel_width == 0:
dm.update_display() # Display empty background
return
# Attempt to use pre-rendered cache for scrolling TTF fonts
if self.text_image_cache and self.scroll_enabled and self.text_pixel_width > matrix_width:
current_scroll_int = int(self.scroll_pos)
source_x1 = current_scroll_int
source_x2 = current_scroll_int + matrix_width
if source_x2 <= self.text_pixel_width:
# Normal case: Paste single crop from cache
segment = self.text_image_cache.crop((source_x1, 0, source_x2, matrix_height))
dm.image.paste(segment, (0, 0))
else:
# Use PIL's textbbox for TTF height
bbox = self.display_manager.draw.textbbox((0, 0), self.text, font=self.font)
text_height = bbox[3] - bbox[1]
y = (matrix_height - text_height) // 2
# Adjust y based on baseline for PIL fonts if needed
if not isinstance(self.font, freetype.Face):
# Small adjustment often needed for PIL's draw.text
y -= bbox[1] # Subtract the top bearing
except Exception as e:
logger.warning(f"Could not calculate text height accurately: {e}. Using default.")
y = 0 # Default to top
if self.scroll_enabled and self.text_width > matrix_width:
# Scrolling text
x = matrix_width - int(self.scroll_pos)
# Draw text using display_manager's draw_text method
self.display_manager.draw_text(
text=self.text,
x=x,
y=y,
color=self.text_color,
font=self.font # Pass the specific font instance
)
# Wrap-around case: Paste two parts from cache for seamless loop
width1 = self.text_pixel_width - source_x1
if width1 > 0: # Should always be true if source_x2 > self.text_pixel_width
segment1 = self.text_image_cache.crop((source_x1, 0, self.text_pixel_width, matrix_height))
dm.image.paste(segment1, (0, 0))
remaining_width_for_screen = matrix_width - width1
if remaining_width_for_screen > 0:
segment2 = self.text_image_cache.crop((0, 0, remaining_width_for_screen, matrix_height))
# Paste segment2 at the correct x-offset on the screen
dm.image.paste(segment2, (width1 if width1 > 0 else 0, 0))
else:
# Static text (centered horizontally)
x = (matrix_width - self.text_width) // 2
self.display_manager.draw_text(
text=self.text,
x=x,
y=y,
color=self.text_color,
font=self.font # Pass the specific font instance
)
# No need to call update_display here, controller should handle it after calling display
# Add the call to update the display here
self.display_manager.update_display()
# Reset scroll position for next time if not scrolling
# self.last_update_time = time.time() # Reset time tracking if static
# Fallback to direct drawing (e.g., BDF, static text, or text fits screen)
# Calculate Y position (center vertically) - original logic
# This part needs to be robust for both BDF and TTF (when not cached)
final_y_for_draw = 0
try:
if isinstance(self.font, freetype.Face):
text_render_height = self.font.size.height >> 6
final_y_for_draw = (matrix_height - text_render_height) // 2
else: # PIL TTF Font
# Use dm.draw for live textbbox calculation on the current frame's draw context
pil_bbox = dm.draw.textbbox((0, 0), self.text, font=self.font)
text_render_height = pil_bbox[3] - pil_bbox[1]
final_y_for_draw = (matrix_height - text_render_height) // 2 - pil_bbox[1] # Adjust for PIL's baseline
except Exception as e:
logger.warning(f"TextDisplay: Could not calculate text height accurately for direct drawing: {e}. Using y=0.", exc_info=True)
final_y_for_draw = 0
if self.scroll_enabled and self.text_pixel_width > matrix_width:
# Scrolling text (direct drawing path, e.g., for BDF or if cache failed)
# This x calculation makes text appear from right and scroll left
x_draw_pos = matrix_width - int(self.scroll_pos)
dm.draw_text(
text=self.text, x=x_draw_pos, y=final_y_for_draw,
color=self.text_color, font=self.font
)
else:
# Static text (centered horizontally)
x_draw_pos = (matrix_width - self.text_pixel_width) // 2
dm.draw_text(
text=self.text, x=x_draw_pos, y=final_y_for_draw,
color=self.text_color, font=self.font
)
dm.update_display()
# Add setters to regenerate cache if properties change
def set_text(self, new_text: str):
self.text = new_text
self._regenerate_renderings()
def set_font(self, font_path: str, font_size: int):
self.font_path = font_path
self.font_size = font_size
self.font = self._load_font()
self._regenerate_renderings()
def set_color(self, text_color: tuple, bg_color: tuple):
self.text_color = text_color
self.bg_color = bg_color
# Background color change requires cache regeneration
# Text color is part of cache, so also regenerate.
self._regenerate_renderings()
def set_scroll_enabled(self, enabled: bool):
self.scroll_enabled = enabled
self.scroll_pos = 0.0 # Reset scroll when state changes
# No need to regenerate cache, just affects display logic
def set_scroll_speed(self, speed: float):
self.scroll_speed = speed
# No need to regenerate cache