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Diffstat (limited to 'libs/litehtml/src/flex_line.cpp')
| -rw-r--r-- | libs/litehtml/src/flex_line.cpp | 454 |
1 files changed, 454 insertions, 0 deletions
diff --git a/libs/litehtml/src/flex_line.cpp b/libs/litehtml/src/flex_line.cpp new file mode 100644 index 0000000000..5f966b3b15 --- /dev/null +++ b/libs/litehtml/src/flex_line.cpp @@ -0,0 +1,454 @@ +#include "html.h" +#include "flex_line.h" +#include "flex_item.h" +#include "render_item.h" + +void litehtml::flex_line::distribute_free_space(int container_main_size) +{ + // Determine the used flex factor. Sum the outer hypothetical main sizes of all items on the line. + // If the sum is less than the flex container’s inner main size, use the flex grow factor for the + // rest of this algorithm; otherwise, use the flex shrink factor. + int initial_free_space = container_main_size - base_size; + bool grow; + int total_flex_factor; + if(initial_free_space < 0) + { + grow = false; + total_flex_factor = total_shrink; + // Flex values between 0 and 1 have a somewhat special behavior: when the sum of the flex values on the line + // is less than 1, they will take up less than 100% of the free space. + // https://www.w3.org/TR/css-flexbox-1/#valdef-flex-flex-grow + if(total_flex_factor < 1000) + { + for(auto &item : items) + { + item->main_size += initial_free_space * item->shrink / 1000; + } + return; + } + } else + { + grow = true; + total_flex_factor = total_grow; + // Flex values between 0 and 1 have a somewhat special behavior: when the sum of the flex values on the line + // is less than 1, they will take up less than 100% of the free space. + // https://www.w3.org/TR/css-flexbox-1/#valdef-flex-flex-grow + if(total_flex_factor < 1000) + { + for(auto &item : items) + { + item->main_size += initial_free_space * item->grow / 1000; + } + return; + } + } + + if(total_flex_factor > 0) + { + bool processed = true; + while (processed) + { + int sum_scaled_flex_shrink_factor = 0; + int sum_flex_factors = 0; + int remaining_free_space = container_main_size; + int total_not_frozen = 0; + for (auto &item: items) + { + if (!item->frozen) + { + sum_scaled_flex_shrink_factor += item->scaled_flex_shrink_factor; + if(grow) + { + sum_flex_factors += item->grow; + } else + { + sum_flex_factors += item->shrink; + } + remaining_free_space -= item->base_size; + total_not_frozen++; + } else + { + remaining_free_space -= item->main_size; + } + } + // Check for flexible items. If all the flex items on the line are frozen, free space has + // been distributed; exit this loop. + if (!total_not_frozen) break; + + remaining_free_space = abs(remaining_free_space); + // c. Distribute free space proportional to the flex factors. + // If the remaining free space is zero + // Do nothing. + if (!remaining_free_space) + { + processed = false; + } else + { + int total_clamped = 0; + for (auto &item: items) + { + if (!item->frozen) + { + if(!grow) + { + // If using the flex shrink factor + // For every unfrozen item on the line, multiply its flex shrink factor by its + // inner flex base size, and note this as its scaled flex shrink factor. Find + // the ratio of the item’s scaled flex shrink factor to the sum of the scaled + // flex shrink factors of all unfrozen items on the line. Set the item’s target + // main size to its flex base size minus a fraction of the absolute value of the + // remaining free space proportional to the ratio. + int scaled_flex_shrink_factor = item->base_size * item->shrink; + item->main_size = (int) ((float) item->base_size - (float) remaining_free_space * + (float) scaled_flex_shrink_factor / + (float) sum_scaled_flex_shrink_factor); + + // d. Fix min/max violations. Clamp each non-frozen item’s target main size by its used + // min and max main sizes and floor its content-box size at zero. If the item’s target + // main size was made smaller by this, it’s a max violation. If the item’s target main + // size was made larger by this, it’s a min violation. + if (item->main_size <= item->min_size) + { + total_clamped++; + item->main_size = item->min_size; + item->frozen = true; + } + if(!item->max_size.is_default() && item->main_size >= item->max_size) + { + total_clamped++; + item->main_size = item->max_size; + item->frozen = true; + } + } else + { + // If using the flex grow factor + // Find the ratio of the item’s flex grow factor to the sum of the flex grow + // factors of all unfrozen items on the line. Set the item’s target main size to + // its flex base size plus a fraction of the remaining free space proportional + // to the ratio. + item->main_size = (int) ((float) item->base_size + + (float) remaining_free_space * (float) item->grow / + (float) total_flex_factor); + // d. Fix min/max violations. Clamp each non-frozen item’s target main size by its used + // min and max main sizes and floor its content-box size at zero. If the item’s target + // main size was made smaller by this, it’s a max violation. If the item’s target main + // size was made larger by this, it’s a min violation. + if (item->main_size >= container_main_size) + { + total_clamped++; + item->main_size = container_main_size; + item->frozen = true; + } + if(!item->max_size.is_default() && item->main_size >= item->max_size) + { + total_clamped++; + item->main_size = item->max_size; + item->frozen = true; + } + } + } + } + if (total_clamped == 0) processed = false; + } + } + // Distribute remaining after algorithm space + int sum_main_size = 0; + for(auto &item : items) + { + sum_main_size += item->main_size; + } + int free_space = container_main_size - sum_main_size; + if(free_space > 0) + { + for(auto &item : items) + { + if(free_space == 0) break; + item->main_size++; + free_space--; + } + } + } +} + +bool litehtml::flex_line::distribute_main_auto_margins(int free_main_size) +{ + if(free_main_size > 0 && (num_auto_margin_main_start || num_auto_margin_main_end)) + { + int add = (int) (free_main_size / (items.size() * 2)); + for (auto &item: items) + { + if(!item->auto_margin_main_start.is_default()) + { + item->auto_margin_main_start = add; + item->main_size += add; + main_size += add; + free_main_size -= add; + } + if(!item->auto_margin_main_end.is_default()) + { + item->auto_margin_main_end = add; + item->main_size += add; + main_size += add; + free_main_size -= add; + } + } + while (free_main_size > 0) + { + for (auto &item: items) + { + if(!item->auto_margin_main_start.is_default()) + { + item->auto_margin_main_start = item->auto_margin_main_start + 1; + free_main_size--; + if(!free_main_size) break; + } + if(!item->auto_margin_main_end.is_default()) + { + item->auto_margin_main_end = item->auto_margin_main_end + 1; + free_main_size--; + if(!free_main_size) break; + } + } + } + return true; + } + return false; +} + +void litehtml::flex_line::init(int container_main_size, bool fit_container, bool is_row_direction, + const litehtml::containing_block_context &self_size, + litehtml::formatting_context *fmt_ctx) +{ + cross_size = 0; + main_size = 0; + first_baseline.set(0, baseline::baseline_type_none); + last_baseline.set(0, baseline::baseline_type_none); + + if(!fit_container) + { + distribute_free_space(container_main_size); + } + + if(is_row_direction) + { + def_value<int> first_baseline_top = 0; + def_value<int> first_baseline_bottom = 0; + def_value<int> last_baseline_top = 0; + def_value<int> last_baseline_bottom = 0; + int non_baseline_height = 0; + + // Calculate maximum cross size + def_value<int> max_cross_size(0); + if(self_size.height.type != containing_block_context::cbc_value_type_auto) + { + max_cross_size = self_size.height; + } + if(self_size.max_height.type != containing_block_context::cbc_value_type_none) + { + if(max_cross_size.is_default()) + { + max_cross_size = self_size.max_height; + } else + { + max_cross_size = std::max((int) max_cross_size, (int) self_size.max_height); + } + } + + /// Render items into new size + /// Find line cross_size + /// Find line first/last baseline + for (auto &item: items) + { + item->el->render(0, + 0, + self_size.new_width(item->main_size - item->el->content_offset_width(), containing_block_context::size_mode_exact_width), fmt_ctx, false); + + if((item->align & 0xFF) == flex_align_items_baseline) + { + if(item->align & flex_align_items_last) + { + last_baseline.type(reverse_cross ? baseline::baseline_type_top : baseline::baseline_type_bottom); + + int top = -item->el->get_last_baseline(); + int bottom = top + item->el->height(); + + if(last_baseline_top.is_default()) last_baseline_top = top; + else last_baseline_top = std::min((int) last_baseline_top, top); + + if(last_baseline_bottom.is_default()) last_baseline_bottom = bottom; + else last_baseline_bottom = std::max((int)last_baseline_bottom, bottom); + } else + { + first_baseline.type(reverse_cross ? baseline::baseline_type_bottom : baseline::baseline_type_top); + int top = -item->el->get_first_baseline(); + int bottom = top + item->el->height(); + + if(first_baseline_top.is_default()) first_baseline_top = top; + else first_baseline_top = std::min((int) first_baseline_top, top); + + if(first_baseline_bottom.is_default()) first_baseline_bottom = bottom; + else first_baseline_bottom = std::max((int) first_baseline_bottom, bottom); + } + } else + { + non_baseline_height = std::max(non_baseline_height, item->el->height()); + } + main_size += item->el->width(); + } + + cross_size = std::max(first_baseline_bottom - first_baseline_top,last_baseline_bottom - last_baseline_top); + cross_size = std::max(cross_size, non_baseline_height); + if(!max_cross_size.is_default() && cross_size > max_cross_size) + { + cross_size = max_cross_size; + } + + first_baseline.calc(first_baseline_top, first_baseline_bottom); + last_baseline.calc(last_baseline_top, last_baseline_bottom); + } else + { + // Calculate maximum cross size + def_value<int> max_cross_size(0); + if(self_size.width.type != containing_block_context::cbc_value_type_auto) + { + max_cross_size = self_size.width; + } + if(self_size.max_width.type != containing_block_context::cbc_value_type_none) + { + if(max_cross_size.is_default()) + { + max_cross_size = self_size.max_width; + } else + { + max_cross_size = std::max((int) max_cross_size, (int) self_size.max_width); + } + } + + for (auto &item: items) + { + int el_ret_width = item->el->render(0, + 0, + self_size, fmt_ctx, false); + item->el->render(0, + 0, + self_size.new_width_height(el_ret_width - item->el->content_offset_width(), + item->main_size - item->el->content_offset_height(), + containing_block_context::size_mode_exact_width | + containing_block_context::size_mode_exact_height), + fmt_ctx, false); + main_size += item->el->height(); + cross_size = std::max(cross_size, item->el->width()); + } + if(!max_cross_size.is_default() && cross_size > max_cross_size) + { + cross_size = max_cross_size; + } + } +} + +int litehtml::flex_line::calculate_items_position(int container_main_size, + flex_justify_content justify_content, + bool is_row_direction, + const containing_block_context &self_size, + formatting_context *fmt_ctx) +{ + /// Distribute main axis free space for auto-margins + int free_main_size = container_main_size - main_size; + distribute_main_auto_margins(free_main_size); + free_main_size = container_main_size - main_size; + + /// Fix justify-content property + switch (justify_content) + { + case flex_justify_content_left: + case flex_justify_content_right: + if(!is_row_direction) + { + justify_content = flex_justify_content_start; + } + break; + case flex_justify_content_space_between: + // If the leftover free-space is negative or there is only a single flex item on the line, this + // value is identical to flex-start. + if(items.size() == 1 || free_main_size < 0) justify_content = flex_justify_content_flex_start; + break; + case flex_justify_content_space_around: + case flex_justify_content_space_evenly: + // If the leftover free-space is negative or there is only a single flex item on the line, this + // value is identical to center + if(items.size() == 1 || free_main_size < 0) justify_content = flex_justify_content_center; + break; + default: + break; + } + + /// Distribute free main size using justify-content property + int main_pos = 0; + int add_before_item = 0; + int add_after_item = 0; + int item_remainder = 0; + + /// find initial main position and spaces between items + switch (justify_content) + { + + case flex_justify_content_right: + main_pos = free_main_size; + break; + case flex_justify_content_left: + case flex_justify_content_start: + main_pos = 0; + break; + case flex_justify_content_end: + main_pos = free_main_size; + break; + case flex_justify_content_flex_end: + if(!reverse_main) + { + main_pos = free_main_size; + } + break; + case flex_justify_content_center: + main_pos = free_main_size / 2; + break; + case flex_justify_content_space_between: + add_after_item = free_main_size / ((int) items.size() - 1); + item_remainder = free_main_size - (add_after_item * ((int) items.size() - 1)); + break; + case flex_justify_content_space_around: + add_after_item = add_before_item = free_main_size / ((int) items.size() * 2); + item_remainder = free_main_size - (add_after_item * (int) items.size() * 2); + break; + case flex_justify_content_space_evenly: + add_before_item = free_main_size / ((int) items.size() + 1); + item_remainder = free_main_size - add_before_item * ((int) items.size() + 1); + break; + default: + if(reverse_main) + { + main_pos = free_main_size; + } + break; + } + + /// Place all items in main and cross positions + int height = 0; + for(auto &item : items) + { + main_pos += add_before_item; + if(add_before_item > 0 && item_remainder > 0) + { + main_pos++; + item_remainder--; + } + item->place(*this, main_pos, self_size, fmt_ctx); + main_pos += item->get_el_main_size() + add_after_item; + if(add_after_item > 0 && item_remainder > 0) + { + main_pos++; + item_remainder--; + } + height = std::max(height, item->el->bottom()); + } + return height; +} |