diff options
Diffstat (limited to 'src/canvas/drawing_utils.rs')
-rw-r--r-- | src/canvas/drawing_utils.rs | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/src/canvas/drawing_utils.rs b/src/canvas/drawing_utils.rs new file mode 100644 index 00000000..2d53d064 --- /dev/null +++ b/src/canvas/drawing_utils.rs @@ -0,0 +1,104 @@ +use crate::app; + +/// A somewhat jury-rigged solution to simulate a variable intrinsic layout for +/// table widths. Note that this will do one main pass to try to properly +/// allocate widths. This will thus potentially cut off latter elements +/// (return size of 0) if it is too small (threshold), but will try its best. +/// +/// `width thresholds` and `desired_widths_ratio` should be the same length. +/// Otherwise bad things happen. +pub fn get_variable_intrinsic_widths( + total_width: u16, desired_widths_ratio: &[f64], width_thresholds: &[usize], +) -> (Vec<u16>, usize) { + let num_widths = desired_widths_ratio.len(); + let mut resulting_widths: Vec<u16> = vec![0; num_widths]; + let mut last_index = 0; + + let mut remaining_width = (total_width - (num_widths as u16 - 1)) as i32; // Required for spaces... + let desired_widths = desired_widths_ratio + .iter() + .map(|&desired_width_ratio| (desired_width_ratio * total_width as f64) as i32) + .collect::<Vec<_>>(); + + for (itx, desired_width) in desired_widths.into_iter().enumerate() { + resulting_widths[itx] = if desired_width < width_thresholds[itx] as i32 { + // Try to take threshold, else, 0 + if remaining_width < width_thresholds[itx] as i32 { + 0 + } else { + remaining_width -= width_thresholds[itx] as i32; + width_thresholds[itx] as u16 + } + } else { + // Take as large as possible + if remaining_width < desired_width { + // Check the biggest chunk possible + if remaining_width < width_thresholds[itx] as i32 { + 0 + } else { + let temp_width = remaining_width; + remaining_width = 0; + temp_width as u16 + } + } else { + remaining_width -= desired_width; + desired_width as u16 + } + }; + + if resulting_widths[itx] == 0 { + break; + } else { + last_index += 1; + } + } + + // Simple redistribution tactic - if there's any space left, split it evenly amongst all members + if last_index < num_widths { + let for_all_widths = (remaining_width / last_index as i32) as u16; + let mut remainder = remaining_width % last_index as i32; + + for resulting_width in &mut resulting_widths { + *resulting_width += for_all_widths; + if remainder > 0 { + *resulting_width += 1; + remainder -= 1; + } + } + } + + (resulting_widths, last_index) +} + +pub fn get_start_position( + num_rows: u64, scroll_direction: &app::ScrollDirection, previously_scrolled_position: &mut u64, + currently_selected_position: u64, +) -> u64 { + match scroll_direction { + app::ScrollDirection::DOWN => { + if currently_selected_position < *previously_scrolled_position + num_rows { + // If, using previous_scrolled_position, we can see the element + // (so within that and + num_rows) just reuse the current previously scrolled position + *previously_scrolled_position + } else if currently_selected_position >= num_rows { + // Else if the current position past the last element visible in the list, omit + // until we can see that element + *previously_scrolled_position = currently_selected_position - num_rows; + currently_selected_position - num_rows + } else { + // Else, if it is not past the last element visible, do not omit anything + 0 + } + } + app::ScrollDirection::UP => { + if currently_selected_position <= *previously_scrolled_position { + // If it's past the first element, then show from that element downwards + *previously_scrolled_position = currently_selected_position; + currently_selected_position + } else { + // Else, don't change what our start position is from whatever it is set to! + *previously_scrolled_position + } + } + } +} |