Split measure functions out of the measure example

examples/common/image.rs

@@ -0,0 +1,18 @@
+use taffy::geometry::Size;
+
+pub struct ImageContext {
+ pub width: f32,
+ pub height: f32,
+}
+
+pub fn image_measure_function(
+ known_dimensions: taffy::geometry::Size<Option<f32>>,
+ image_context: &ImageContext,
+) -> taffy::geometry::Size<f32> {
+ match (known_dimensions.width, known_dimensions.height) {
+ (Some(width), Some(height)) => Size { width, height },
+ (Some(width), None) => Size { width, height: (width / image_context.width) * image_context.height },
+ (None, Some(height)) => Size { width: (height / image_context.height) * image_context.width, height },
+ (None, None) => Size { width: image_context.width, height: image_context.height },
+ }
+}

examples/common/text.rs

@@ -0,0 +1,70 @@
+pub const LOREM_IPSUM : &str = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.";
+
+pub struct FontMetrics {
+ pub char_width: f32,
+ pub char_height: f32,
+}
+
+#[allow(dead_code)]
+pub enum WritingMode {
+ Horizontal,
+ Vertical,
+}
+
+pub struct TextContext {
+ pub text_content: String,
+ pub writing_mode: WritingMode,
+}
+
+pub fn text_measure_function(
+ known_dimensions: taffy::geometry::Size<Option<f32>>,
+ available_space: taffy::geometry::Size<taffy::style::AvailableSpace>,
+ text_context: &TextContext,
+ font_metrics: &FontMetrics,
+) -> taffy::geometry::Size<f32> {
+ use taffy::geometry::AbsoluteAxis;
+ use taffy::prelude::*;
+
+ let inline_axis = match text_context.writing_mode {
+ WritingMode::Horizontal => AbsoluteAxis::Horizontal,
+ WritingMode::Vertical => AbsoluteAxis::Vertical,
+ };
+ let block_axis = inline_axis.other_axis();
+ let words: Vec<&str> = text_context.text_content.split_whitespace().collect();
+
+ if words.is_empty() {
+ return Size::ZERO;
+ }
+
+ let min_line_length: usize = words.iter().map(|line| line.len()).max().unwrap_or(0);
+ let max_line_length: usize = words.iter().map(|line| line.len()).sum();
+ let inline_size =
+ known_dimensions.get_abs(inline_axis).unwrap_or_else(|| match available_space.get_abs(inline_axis) {
+ AvailableSpace::MinContent => min_line_length as f32 * font_metrics.char_width,
+ AvailableSpace::MaxContent => max_line_length as f32 * font_metrics.char_width,
+ AvailableSpace::Definite(inline_size) => inline_size
+ .min(max_line_length as f32 * font_metrics.char_width)
+ .max(min_line_length as f32 * font_metrics.char_width),
+ });
+ let block_size = known_dimensions.get_abs(block_axis).unwrap_or_else(|| {
+ let inline_line_length = (inline_size / font_metrics.char_width).floor() as usize;
+ let mut line_count = 1;
+ let mut current_line_length = 0;
+ for word in &words {
+ if current_line_length + word.len() > inline_line_length {
+ if current_line_length > 0 {
+ line_count += 1
+ };
+ current_line_length = word.len();
+ } else {
+ current_line_length += word.len();
+ };
+ }
+ (line_count as f32) * font_metrics.char_height
+ });
+
+ match text_context.writing_mode {
+ WritingMode::Horizontal => Size { width: inline_size, height: block_size },
+ WritingMode::Vertical => Size { width: block_size, height: inline_size },
+ }
+}

examples/measure.rs

@@ -1,28 +1,35 @@
+mod common {
+ pub mod image;
+ pub mod text;
+}
+use common::image::{image_measure_function, ImageContext};
+use common::text::{text_measure_function, FontMetrics, TextContext, WritingMode, LOREM_IPSUM};
 use taffy::prelude::*;
 
-const LOREM_IPSUM : &str = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.";
-
-struct FontMetrics {
- char_width: f32,
- char_height: f32,
-}
-enum WritingMode {
- Horizontal,
- Vertical,
-}
-struct TextContext {
- text_content: String,
- writing_mode: WritingMode,
-}
-struct ImageContext {
- width: f32,
- height: f32,
-}
 enum NodeContext {
  Text(TextContext),
  Image(ImageContext),
 }
 
+fn measure_function(
+ known_dimensions: taffy::geometry::Size<Option<f32>>,
+ available_space: taffy::geometry::Size<taffy::style::AvailableSpace>,
+ node_context: Option<&mut NodeContext>,
+ font_metrics: &FontMetrics,
+) -> Size<f32> {
+ if let Size { width: Some(width), height: Some(height) } = known_dimensions {
+ return Size { width, height };
+ }
+
+ match node_context {
+ None => Size::ZERO,
+ Some(NodeContext::Text(text_context)) => {
+ text_measure_function(known_dimensions, available_space, &*text_context, font_metrics)
+ }
+ Some(NodeContext::Image(image_context)) => image_measure_function(known_dimensions, image_context),
+ }
+}
+
 fn main() -> Result<(), taffy::TaffyError> {
  let mut taffy: Taffy<NodeContext> = Taffy::new();
 
@@ -60,87 +67,3 @@ fn main() -> Result<(), taffy::TaffyError> {
 
  Ok(())
 }
-
-fn measure_function(
- known_dimensions: taffy::geometry::Size<Option<f32>>,
- available_space: taffy::geometry::Size<taffy::style::AvailableSpace>,
- node_context: Option<&mut NodeContext>,
- font_metrics: &FontMetrics,
-) -> Size<f32> {
- if let Size { width: Some(width), height: Some(height) } = known_dimensions {
- return Size { width, height };
- }
-
- match node_context {
- None => Size::ZERO,
- Some(NodeContext::Text(text_context)) => {
- text_measure_function(known_dimensions, available_space, &*text_context, font_metrics)
- }
- Some(NodeContext::Image(image_context)) => image_measure_function(known_dimensions, image_context),
- }
-}
-
-fn image_measure_function(
- known_dimensions: taffy::geometry::Size<Option<f32>>,
- image_context: &ImageContext,
-) -> taffy::geometry::Size<f32> {
- match (known_dimensions.width, known_dimensions.height) {
- (Some(width), Some(height)) => Size { width, height },
- (Some(width), None) => Size { width, height: (width / image_context.width) * image_context.height },
- (None, Some(height)) => Size { width: (height / image_context.height) * image_context.width, height },
- (None, None) => Size { width: image_context.width, height: image_context.height },
- }
-}
-
-fn text_measure_function(
- known_dimensions: taffy::geometry::Size<Option<f32>>,
- available_space: taffy::geometry::Size<taffy::style::AvailableSpace>,
- text_context: &TextContext,
- font_metrics: &FontMetrics,
-) -> taffy::geometry::Size<f32> {
- use taffy::geometry::AbsoluteAxis;
- use taffy::prelude::*;
-
- let inline_axis = match text_context.writing_mode {
- WritingMode::Horizontal => AbsoluteAxis::Horizontal,
- WritingMode::Vertical => AbsoluteAxis::Vertical,
- };
- let block_axis = inline_axis.other_axis();
- let words: Vec<&str> = text_context.text_content.split_whitespace().collect();
-
- if words.is_empty() {
- return Size::ZERO;
- }
-
- let min_line_length: usize = words.iter().map(|line| line.len()).max().unwrap_or(0);
- let max_line_length: usize = words.iter().map(|line| line.len()).sum();
- let inline_size =
- known_dimensions.get_abs(inline_axis).unwrap_or_else(|| match available_space.get_abs(inline_axis) {
- AvailableSpace::MinContent => min_line_length as f32 * font_metrics.char_width,
- AvailableSpace::MaxContent => max_line_length as f32 * font_metrics.char_width,
- AvailableSpace::Definite(inline_size) => inline_size
- .min(max_line_length as f32 * font_metrics.char_width)
- .max(min_line_length as f32 * font_metrics.char_width),
- });
- let block_size = known_dimensions.get_abs(block_axis).unwrap_or_else(|| {
- let inline_line_length = (inline_size / font_metrics.char_width).floor() as usize;
- let mut line_count = 1;
- let mut current_line_length = 0;
- for word in &words {
- if current_line_length + word.len() > inline_line_length {
- if current_line_length > 0 {
- line_count += 1
- };
- current_line_length = word.len();
- } else {
- current_line_length += word.len();
- };
- }
- (line_count as f32) * font_metrics.char_height
- });
-
- match text_context.writing_mode {
- WritingMode::Horizontal => Size { width: inline_size, height: block_size },
- WritingMode::Vertical => Size { width: block_size, height: inline_size },
- }
-}