From 5180025de5d6757865a17bd7e3f5c37fbae7d727 Mon Sep 17 00:00:00 2001 From: ocornut Date: Tue, 1 Dec 2020 17:31:59 +0100 Subject: [PATCH] Tables: moved + renamed TableSetupDrawChannels(), TableMergeDrawChannels() to their own section. --- imgui_internal.h | 4 +- imgui_tables.cpp | 500 ++++++++++++++++++++++++----------------------- 2 files changed, 257 insertions(+), 247 deletions(-) diff --git a/imgui_internal.h b/imgui_internal.h index b9a2ca1c2..ba58c2bff 100644 --- a/imgui_internal.h +++ b/imgui_internal.h @@ -2283,12 +2283,12 @@ namespace ImGui IMGUI_API ImGuiTable* TableFindByID(ImGuiID id); IMGUI_API bool BeginTableEx(const char* name, ImGuiID id, int columns_count, ImGuiTableFlags flags = 0, const ImVec2& outer_size = ImVec2(0, 0), float inner_width = 0.0f); IMGUI_API void TableBeginApplyRequests(ImGuiTable* table); - IMGUI_API void TableUpdateDrawChannels(ImGuiTable* table); + IMGUI_API void TableSetupDrawChannels(ImGuiTable* table); IMGUI_API void TableUpdateLayout(ImGuiTable* table); IMGUI_API void TableUpdateBorders(ImGuiTable* table); IMGUI_API void TableDrawBorders(ImGuiTable* table); IMGUI_API void TableDrawContextMenu(ImGuiTable* table); - IMGUI_API void TableReorderDrawChannelsForMerge(ImGuiTable* table); + IMGUI_API void TableMergeDrawChannels(ImGuiTable* table); IMGUI_API void TableSortSpecsSanitize(ImGuiTable* table); IMGUI_API void TableSortSpecsBuild(ImGuiTable* table); IMGUI_API void TableFixColumnSortDirection(ImGuiTableColumn* column); diff --git a/imgui_tables.cpp b/imgui_tables.cpp index 033f9109c..d48fb6675 100644 --- a/imgui_tables.cpp +++ b/imgui_tables.cpp @@ -6,6 +6,7 @@ Index of this file: // [SECTION] Tables: BeginTable, EndTable, etc. +// [SECTION] Tables: Drawing // [SECTION] Tables: Sorting // [SECTION] Tables: Headers // [SECTION] Tables: Context Menu @@ -81,7 +82,7 @@ Index of this file: // - TableSetupColumn() user submit columns details (optional) // - TableSetupScrollFreeze() user submit scroll freeze information (optional) // - TableUpdateLayout() [Internal] automatically called by the FIRST call to TableNextRow() or TableHeadersRow(): lock all widths, columns positions, clipping rectangles -// | TableUpdateDrawChannels() - setup ImDrawList channels +// | TableSetupDrawChannels() - setup ImDrawList channels // | TableUpdateBorders() - detect hovering columns for resize, ahead of contents submission // | TableDrawContextMenu() - draw right-click context menu //----------------------------------------------------------------------------- @@ -99,7 +100,7 @@ Index of this file: //----------------------------------------------------------------------------- // - EndTable() user ends the table // | TableDrawBorders() - draw outer borders, inner vertical borders -// | TableReorderDrawChannelsForMerge() - merge draw channels if clipping isn't required +// | TableMergeDrawChannels() - merge draw channels if clipping isn't required // | EndChild() - (if ScrollX/ScrollY is set) //----------------------------------------------------------------------------- @@ -938,7 +939,7 @@ void ImGui::TableUpdateLayout(ImGuiTable* table) table->Flags &= ~ImGuiTableFlags_Resizable; // Allocate draw channels - TableUpdateDrawChannels(table); + TableSetupDrawChannels(table); // Borders if (table->Flags & ImGuiTableFlags_Resizable) @@ -1111,7 +1112,7 @@ void ImGui::EndTable() // Flatten channels and merge draw calls if ((table->Flags & ImGuiTableFlags_NoClip) == 0) - TableReorderDrawChannelsForMerge(table); + TableMergeDrawChannels(table); table->DrawSplitter.Merge(inner_window->DrawList); if (!(table->Flags & ImGuiTableFlags_ScrollX) && inner_window != outer_window) @@ -1394,247 +1395,6 @@ void ImGui::TableSetColumnWidth(int column_n, float width) } } -// Allocate draw channels. Called by TableUpdateLayout() -// - We allocate them following storage order instead of display order so reordering columns won't needlessly -// increase overall dormant memory cost. -// - We isolate headers draw commands in their own channels instead of just altering clip rects. -// This is in order to facilitate merging of draw commands. -// - After crossing FreezeRowsCount, all columns see their current draw channel changed to a second set of channels. -// - We only use the dummy draw channel so we can push a null clipping rectangle into it without affecting other -// channels, while simplifying per-row/per-cell overhead. It will be empty and discarded when merged. -// - We allocate 1 or 2 background draw channels. This is because we know PushTableBackground() is only used for -// horizontal spanning. If we allowed vertical spanning we'd need one background draw channel per merge group (1-4). -// Draw channel allocation (before merging): -// - NoClip --> 2+D+1 channels: bg0 + bg1 + foreground (same clip rect == 1 draw call) (FIXME-TABLE: could merge bg1 and foreground?) -// - Clip --> 2+D+N channels -// - FreezeRows --> 2+D+N*2 (unless scrolling value is zero) -// - FreezeRows || FreezeColunns --> 3+D+N*2 (unless scrolling value is zero) -// Where D is 1 if any column is clipped or hidden (dummy channel) otherwise 0. -void ImGui::TableUpdateDrawChannels(ImGuiTable* table) -{ - const int freeze_row_multiplier = (table->FreezeRowsCount > 0) ? 2 : 1; - const int channels_for_row = (table->Flags & ImGuiTableFlags_NoClip) ? 1 : table->ColumnsEnabledCount; - const int channels_for_bg = 1 + 1 * freeze_row_multiplier; - const int channels_for_dummy = (table->ColumnsEnabledCount < table->ColumnsCount || table->EnabledUnclippedMaskByIndex != table->EnabledMaskByIndex) ? +1 : 0; - const int channels_total = channels_for_bg + (channels_for_row * freeze_row_multiplier) + channels_for_dummy; - table->DrawSplitter.Split(table->InnerWindow->DrawList, channels_total); - table->DummyDrawChannel = (ImU8)((channels_for_dummy > 0) ? channels_total - 1 : -1); - table->Bg1DrawChannelCurrent = TABLE_DRAW_CHANNEL_BG1_FROZEN; - table->Bg1DrawChannelUnfrozen = (ImU8)((table->FreezeRowsCount > 0) ? 2 + channels_for_row : TABLE_DRAW_CHANNEL_BG1_FROZEN); - - int draw_channel_current = 2; - for (int column_n = 0; column_n < table->ColumnsCount; column_n++) - { - ImGuiTableColumn* column = &table->Columns[column_n]; - if (!column->IsClipped) - { - column->DrawChannelFrozen = (ImU8)(draw_channel_current); - column->DrawChannelUnfrozen = (ImU8)(draw_channel_current + (table->FreezeRowsCount > 0 ? channels_for_row + 1 : 0)); - if (!(table->Flags & ImGuiTableFlags_NoClip)) - draw_channel_current++; - } - else - { - column->DrawChannelFrozen = column->DrawChannelUnfrozen = table->DummyDrawChannel; - } - column->DrawChannelCurrent = column->DrawChannelFrozen; - } -} - -// This function reorder draw channels based on matching clip rectangle, to facilitate merging them. Called by EndTable(). -// -// Columns where the contents didn't stray off their local clip rectangle can be merged. To achieve -// this we merge their clip rect and make them contiguous in the channel list, so they can be merged -// by the call to DrawSplitter.Merge() following to the call to this function. -// -// We reorder draw commands by arranging them into a maximum of 4 distinct groups: -// -// 1 group: 2 groups: 2 groups: 4 groups: -// [ 0. ] no freeze [ 0. ] row freeze [ 01 ] col freeze [ 01 ] row+col freeze -// [ .. ] or no scroll [ 2. ] and v-scroll [ .. ] and h-scroll [ 23 ] and v+h-scroll -// -// Each column itself can use 1 channel (row freeze disabled) or 2 channels (row freeze enabled). -// When the contents of a column didn't stray off its limit, we move its channels into the corresponding group -// based on its position (within frozen rows/columns groups or not). -// At the end of the operation our 1-4 groups will each have a ImDrawCmd using the same ClipRect. -// -// This function assume that each column are pointing to a distinct draw channel, -// otherwise merge_group->ChannelsCount will not match set bit count of merge_group->ChannelsMask. -// -// Column channels will not be merged into one of the 1-4 groups in the following cases: -// - The contents stray off its clipping rectangle (we only compare the MaxX value, not the MinX value). -// Direct ImDrawList calls won't be taken into account by default, if you use them make sure the ImGui:: bounds -// matches, by e.g. calling SetCursorScreenPos(). -// - The channel uses more than one draw command itself. We drop all our attempt at merging stuff here.. -// we could do better but it's going to be rare and probably not worth the hassle. -// Columns for which the draw channel(s) haven't been merged with other will use their own ImDrawCmd. -// -// This function is particularly tricky to understand.. take a breath. -void ImGui::TableReorderDrawChannelsForMerge(ImGuiTable* table) -{ - ImGuiContext& g = *GImGui; - ImDrawListSplitter* splitter = &table->DrawSplitter; - const bool has_freeze_v = (table->FreezeRowsCount > 0); - const bool has_freeze_h = (table->FreezeColumnsCount > 0); - - // Track which groups we are going to attempt to merge, and which channels goes into each group. - struct MergeGroup - { - ImRect ClipRect; - int ChannelsCount; - ImBitArray ChannelsMask; - }; - int merge_group_mask = 0x00; - MergeGroup merge_groups[4]; - memset(merge_groups, 0, sizeof(merge_groups)); - - // 1. Scan channels and take note of those which can be merged - for (int column_n = 0; column_n < table->ColumnsCount; column_n++) - { - if (!(table->EnabledUnclippedMaskByIndex & ((ImU64)1 << column_n))) - continue; - ImGuiTableColumn* column = &table->Columns[column_n]; - - const int merge_group_sub_count = has_freeze_v ? 2 : 1; - for (int merge_group_sub_n = 0; merge_group_sub_n < merge_group_sub_count; merge_group_sub_n++) - { - const int channel_no = (merge_group_sub_n == 0) ? column->DrawChannelFrozen : column->DrawChannelUnfrozen; - - // Don't attempt to merge if there are multiple draw calls within the column - ImDrawChannel* src_channel = &splitter->_Channels[channel_no]; - if (src_channel->_CmdBuffer.Size > 0 && src_channel->_CmdBuffer.back().ElemCount == 0) - src_channel->_CmdBuffer.pop_back(); - if (src_channel->_CmdBuffer.Size != 1) - continue; - - // Find out the width of this merge group and check if it will fit in our column - // (note that we assume that rendering didn't stray on the left direction. we should need a CursorMinPos to detect it) - if (!(column->Flags & ImGuiTableColumnFlags_NoClip)) - { - float content_max_x; - if (!has_freeze_v) - content_max_x = ImMax(column->ContentMaxXUnfrozen, column->ContentMaxXHeadersUsed); // No row freeze - else if (merge_group_sub_n == 0) - content_max_x = ImMax(column->ContentMaxXFrozen, column->ContentMaxXHeadersUsed); // Row freeze: use width before freeze - else - content_max_x = column->ContentMaxXUnfrozen; // Row freeze: use width after freeze - if (content_max_x > column->ClipRect.Max.x) - continue; - } - - const int merge_group_n = (has_freeze_h && column_n < table->FreezeColumnsCount ? 0 : 1) + (has_freeze_v && merge_group_sub_n == 0 ? 0 : 2); - IM_ASSERT(channel_no < IMGUI_TABLE_MAX_DRAW_CHANNELS); - MergeGroup* merge_group = &merge_groups[merge_group_n]; - if (merge_group->ChannelsCount == 0) - merge_group->ClipRect = ImRect(+FLT_MAX, +FLT_MAX, -FLT_MAX, -FLT_MAX); - merge_group->ChannelsMask.SetBit(channel_no); - merge_group->ChannelsCount++; - merge_group->ClipRect.Add(src_channel->_CmdBuffer[0].ClipRect); - merge_group_mask |= (1 << merge_group_n); - } - - // Invalidate current draw channel - // (we don't clear DrawChannelFrozen/DrawChannelUnfrozen solely to facilitate debugging/later inspection of data) - column->DrawChannelCurrent = (ImU8)-1; - } - - // [DEBUG] Display merge groups -#if 0 - if (g.IO.KeyShift) - for (int merge_group_n = 0; merge_group_n < IM_ARRAYSIZE(merge_groups); merge_group_n++) - { - MergeGroup* merge_group = &merge_groups[merge_group_n]; - if (merge_group->ChannelsCount == 0) - continue; - char buf[32]; - ImFormatString(buf, 32, "MG%d:%d", merge_group_n, merge_group->ChannelsCount); - ImVec2 text_pos = merge_group->ClipRect.Min + ImVec2(4, 4); - ImVec2 text_size = CalcTextSize(buf, NULL); - GetForegroundDrawList()->AddRectFilled(text_pos, text_pos + text_size, IM_COL32(0, 0, 0, 255)); - GetForegroundDrawList()->AddText(text_pos, IM_COL32(255, 255, 0, 255), buf, NULL); - GetForegroundDrawList()->AddRect(merge_group->ClipRect.Min, merge_group->ClipRect.Max, IM_COL32(255, 255, 0, 255)); - } -#endif - - // 2. Rewrite channel list in our preferred order - if (merge_group_mask != 0) - { - // We skip channel 0 (Bg0) and 1 (Bg1 frozen) from the shuffling since they won't move - see channels allocation in TableUpdateDrawChannels(). - const int LEADING_DRAW_CHANNELS = 2; - g.DrawChannelsTempMergeBuffer.resize(splitter->_Count - LEADING_DRAW_CHANNELS); // Use shared temporary storage so the allocation gets amortized - ImDrawChannel* dst_tmp = g.DrawChannelsTempMergeBuffer.Data; - ImBitArray remaining_mask; // We need 132-bit of storage - remaining_mask.ClearBits(); - remaining_mask.SetBitRange(LEADING_DRAW_CHANNELS, splitter->_Count - 1); - remaining_mask.ClearBit(table->Bg1DrawChannelUnfrozen); - IM_ASSERT(has_freeze_v == false || table->Bg1DrawChannelUnfrozen != TABLE_DRAW_CHANNEL_BG1_FROZEN); - int remaining_count = splitter->_Count - (has_freeze_v ? LEADING_DRAW_CHANNELS + 1 : LEADING_DRAW_CHANNELS); - //ImRect host_rect = (table->InnerWindow == table->OuterWindow) ? table->InnerClipRect : table->HostClipRect; - ImRect host_rect = table->HostClipRect; - for (int merge_group_n = 0; merge_group_n < IM_ARRAYSIZE(merge_groups); merge_group_n++) - { - if (int merge_channels_count = merge_groups[merge_group_n].ChannelsCount) - { - MergeGroup* merge_group = &merge_groups[merge_group_n]; - ImRect merge_clip_rect = merge_group->ClipRect; - - // Extend outer-most clip limits to match those of host, so draw calls can be merged even if - // outer-most columns have some outer padding offsetting them from their parent ClipRect. - // The principal cases this is dealing with are: - // - On a same-window table (not scrolling = single group), all fitting columns ClipRect -> will extend and match host ClipRect -> will merge - // - Columns can use padding and have left-most ClipRect.Min.x and right-most ClipRect.Max.x != from host ClipRect -> will extend and match host ClipRect -> will merge - // FIXME-TABLE FIXME-WORKRECT: We are wasting a merge opportunity on tables without scrolling if column doesn't fit - // within host clip rect, solely because of the half-padding difference between window->WorkRect and window->InnerClipRect. - if ((merge_group_n & 1) == 0 || !has_freeze_h) - merge_clip_rect.Min.x = ImMin(merge_clip_rect.Min.x, host_rect.Min.x); - if ((merge_group_n & 2) == 0 || !has_freeze_v) - merge_clip_rect.Min.y = ImMin(merge_clip_rect.Min.y, host_rect.Min.y); - if ((merge_group_n & 1) != 0) - merge_clip_rect.Max.x = ImMax(merge_clip_rect.Max.x, host_rect.Max.x); - if ((merge_group_n & 2) != 0 && (table->Flags & ImGuiTableFlags_NoHostExtendY) == 0) - merge_clip_rect.Max.y = ImMax(merge_clip_rect.Max.y, host_rect.Max.y); -#if 0 - GetOverlayDrawList()->AddRect(merge_group->ClipRect.Min, merge_group->ClipRect.Max, IM_COL32(255, 0, 0, 200), 0.0f, ~0, 1.0f); - GetOverlayDrawList()->AddLine(merge_group->ClipRect.Min, merge_clip_rect.Min, IM_COL32(255, 100, 0, 200)); - GetOverlayDrawList()->AddLine(merge_group->ClipRect.Max, merge_clip_rect.Max, IM_COL32(255, 100, 0, 200)); -#endif - remaining_count -= merge_group->ChannelsCount; - for (int n = 0; n < IM_ARRAYSIZE(remaining_mask.Storage); n++) - remaining_mask.Storage[n] &= ~merge_group->ChannelsMask.Storage[n]; - for (int n = 0; n < splitter->_Count && merge_channels_count != 0; n++) - { - // Copy + overwrite new clip rect - if (!merge_group->ChannelsMask.TestBit(n)) - continue; - merge_group->ChannelsMask.ClearBit(n); - merge_channels_count--; - - ImDrawChannel* channel = &splitter->_Channels[n]; - IM_ASSERT(channel->_CmdBuffer.Size == 1 && merge_clip_rect.Contains(ImRect(channel->_CmdBuffer[0].ClipRect))); - channel->_CmdBuffer[0].ClipRect = merge_clip_rect.ToVec4(); - memcpy(dst_tmp++, channel, sizeof(ImDrawChannel)); - } - } - - // Make sure Bg1DrawChannelUnfrozen appears in the middle of our groups (whereas Bg0 and Bg1 frozen are fixed to 0 and 1) - if (merge_group_n == 1 && has_freeze_v) - memcpy(dst_tmp++, &splitter->_Channels[table->Bg1DrawChannelUnfrozen], sizeof(ImDrawChannel)); - } - - // Append unmergeable channels that we didn't reorder at the end of the list - for (int n = 0; n < splitter->_Count && remaining_count != 0; n++) - { - if (!remaining_mask.TestBit(n)) - continue; - ImDrawChannel* channel = &splitter->_Channels[n]; - memcpy(dst_tmp++, channel, sizeof(ImDrawChannel)); - remaining_count--; - } - IM_ASSERT(dst_tmp == g.DrawChannelsTempMergeBuffer.Data + g.DrawChannelsTempMergeBuffer.Size); - memcpy(splitter->_Channels.Data + LEADING_DRAW_CHANNELS, g.DrawChannelsTempMergeBuffer.Data, (splitter->_Count - LEADING_DRAW_CHANNELS) * sizeof(ImDrawChannel)); - } -} - // We use a default parameter of 'init_width_or_weight == -1', // - with ImGuiTableColumnFlags_WidthFixed, width <= 0 --> init width == auto // - with ImGuiTableColumnFlags_WidthFixed, width > 0 --> init width == manual @@ -2212,6 +1972,256 @@ void ImGui::TableSetBgColor(ImGuiTableBgTarget bg_target, ImU32 color, int colum } } +//------------------------------------------------------------------------- +// [SECTION] Tables: Drawing +//------------------------------------------------------------------------- +// - TablePushBackgroundChannel() [Internal] +// - TablePopBackgroundChannel() [Internal] +// - TableSetupDrawChannels() [Internal] +// - TableReorderDrawChannelsForMerge() [Internal] +//------------------------------------------------------------------------- + +// Allocate draw channels. Called by TableUpdateLayout() +// - We allocate them following storage order instead of display order so reordering columns won't needlessly +// increase overall dormant memory cost. +// - We isolate headers draw commands in their own channels instead of just altering clip rects. +// This is in order to facilitate merging of draw commands. +// - After crossing FreezeRowsCount, all columns see their current draw channel changed to a second set of channels. +// - We only use the dummy draw channel so we can push a null clipping rectangle into it without affecting other +// channels, while simplifying per-row/per-cell overhead. It will be empty and discarded when merged. +// - We allocate 1 or 2 background draw channels. This is because we know PushTableBackground() is only used for +// horizontal spanning. If we allowed vertical spanning we'd need one background draw channel per merge group (1-4). +// Draw channel allocation (before merging): +// - NoClip --> 2+D+1 channels: bg0 + bg1 + foreground (same clip rect == 1 draw call) (FIXME-TABLE: could merge bg1 and foreground?) +// - Clip --> 2+D+N channels +// - FreezeRows --> 2+D+N*2 (unless scrolling value is zero) +// - FreezeRows || FreezeColunns --> 3+D+N*2 (unless scrolling value is zero) +// Where D is 1 if any column is clipped or hidden (dummy channel) otherwise 0. +void ImGui::TableSetupDrawChannels(ImGuiTable* table) +{ + const int freeze_row_multiplier = (table->FreezeRowsCount > 0) ? 2 : 1; + const int channels_for_row = (table->Flags & ImGuiTableFlags_NoClip) ? 1 : table->ColumnsEnabledCount; + const int channels_for_bg = 1 + 1 * freeze_row_multiplier; + const int channels_for_dummy = (table->ColumnsEnabledCount < table->ColumnsCount || table->EnabledUnclippedMaskByIndex != table->EnabledMaskByIndex) ? +1 : 0; + const int channels_total = channels_for_bg + (channels_for_row * freeze_row_multiplier) + channels_for_dummy; + table->DrawSplitter.Split(table->InnerWindow->DrawList, channels_total); + table->DummyDrawChannel = (ImU8)((channels_for_dummy > 0) ? channels_total - 1 : -1); + table->Bg1DrawChannelCurrent = TABLE_DRAW_CHANNEL_BG1_FROZEN; + table->Bg1DrawChannelUnfrozen = (ImU8)((table->FreezeRowsCount > 0) ? 2 + channels_for_row : TABLE_DRAW_CHANNEL_BG1_FROZEN); + + int draw_channel_current = 2; + for (int column_n = 0; column_n < table->ColumnsCount; column_n++) + { + ImGuiTableColumn* column = &table->Columns[column_n]; + if (!column->IsClipped) + { + column->DrawChannelFrozen = (ImU8)(draw_channel_current); + column->DrawChannelUnfrozen = (ImU8)(draw_channel_current + (table->FreezeRowsCount > 0 ? channels_for_row + 1 : 0)); + if (!(table->Flags & ImGuiTableFlags_NoClip)) + draw_channel_current++; + } + else + { + column->DrawChannelFrozen = column->DrawChannelUnfrozen = table->DummyDrawChannel; + } + column->DrawChannelCurrent = column->DrawChannelFrozen; + } +} + +// This function reorder draw channels based on matching clip rectangle, to facilitate merging them. Called by EndTable(). +// For simplicity we call it TableMergeDrawChannels() but in fact it only reorder channels + overwrite ClipRect, +// actual merging is done by table->DrawSplitter.Merge() which is called right after TableMergeDrawChannels(). +// +// Columns where the contents didn't stray off their local clip rectangle can be merged. To achieve +// this we merge their clip rect and make them contiguous in the channel list, so they can be merged +// by the call to DrawSplitter.Merge() following to the call to this function. +// We reorder draw commands by arranging them into a maximum of 4 distinct groups: +// +// 1 group: 2 groups: 2 groups: 4 groups: +// [ 0. ] no freeze [ 0. ] row freeze [ 01 ] col freeze [ 01 ] row+col freeze +// [ .. ] or no scroll [ 2. ] and v-scroll [ .. ] and h-scroll [ 23 ] and v+h-scroll +// +// Each column itself can use 1 channel (row freeze disabled) or 2 channels (row freeze enabled). +// When the contents of a column didn't stray off its limit, we move its channels into the corresponding group +// based on its position (within frozen rows/columns groups or not). +// At the end of the operation our 1-4 groups will each have a ImDrawCmd using the same ClipRect. +// This function assume that each column are pointing to a distinct draw channel, +// otherwise merge_group->ChannelsCount will not match set bit count of merge_group->ChannelsMask. +// +// Column channels will not be merged into one of the 1-4 groups in the following cases: +// - The contents stray off its clipping rectangle (we only compare the MaxX value, not the MinX value). +// Direct ImDrawList calls won't be taken into account by default, if you use them make sure the ImGui:: bounds +// matches, by e.g. calling SetCursorScreenPos(). +// - The channel uses more than one draw command itself. We drop all our attempt at merging stuff here.. +// we could do better but it's going to be rare and probably not worth the hassle. +// Columns for which the draw channel(s) haven't been merged with other will use their own ImDrawCmd. +// +// This function is particularly tricky to understand.. take a breath. +void ImGui::TableMergeDrawChannels(ImGuiTable* table) +{ + ImGuiContext& g = *GImGui; + ImDrawListSplitter* splitter = &table->DrawSplitter; + const bool has_freeze_v = (table->FreezeRowsCount > 0); + const bool has_freeze_h = (table->FreezeColumnsCount > 0); + + // Track which groups we are going to attempt to merge, and which channels goes into each group. + struct MergeGroup + { + ImRect ClipRect; + int ChannelsCount; + ImBitArray ChannelsMask; + }; + int merge_group_mask = 0x00; + MergeGroup merge_groups[4]; + memset(merge_groups, 0, sizeof(merge_groups)); + + // 1. Scan channels and take note of those which can be merged + for (int column_n = 0; column_n < table->ColumnsCount; column_n++) + { + if (!(table->EnabledUnclippedMaskByIndex & ((ImU64)1 << column_n))) + continue; + ImGuiTableColumn* column = &table->Columns[column_n]; + + const int merge_group_sub_count = has_freeze_v ? 2 : 1; + for (int merge_group_sub_n = 0; merge_group_sub_n < merge_group_sub_count; merge_group_sub_n++) + { + const int channel_no = (merge_group_sub_n == 0) ? column->DrawChannelFrozen : column->DrawChannelUnfrozen; + + // Don't attempt to merge if there are multiple draw calls within the column + ImDrawChannel* src_channel = &splitter->_Channels[channel_no]; + if (src_channel->_CmdBuffer.Size > 0 && src_channel->_CmdBuffer.back().ElemCount == 0) + src_channel->_CmdBuffer.pop_back(); + if (src_channel->_CmdBuffer.Size != 1) + continue; + + // Find out the width of this merge group and check if it will fit in our column + // (note that we assume that rendering didn't stray on the left direction. we should need a CursorMinPos to detect it) + if (!(column->Flags & ImGuiTableColumnFlags_NoClip)) + { + float content_max_x; + if (!has_freeze_v) + content_max_x = ImMax(column->ContentMaxXUnfrozen, column->ContentMaxXHeadersUsed); // No row freeze + else if (merge_group_sub_n == 0) + content_max_x = ImMax(column->ContentMaxXFrozen, column->ContentMaxXHeadersUsed); // Row freeze: use width before freeze + else + content_max_x = column->ContentMaxXUnfrozen; // Row freeze: use width after freeze + if (content_max_x > column->ClipRect.Max.x) + continue; + } + + const int merge_group_n = (has_freeze_h && column_n < table->FreezeColumnsCount ? 0 : 1) + (has_freeze_v && merge_group_sub_n == 0 ? 0 : 2); + IM_ASSERT(channel_no < IMGUI_TABLE_MAX_DRAW_CHANNELS); + MergeGroup* merge_group = &merge_groups[merge_group_n]; + if (merge_group->ChannelsCount == 0) + merge_group->ClipRect = ImRect(+FLT_MAX, +FLT_MAX, -FLT_MAX, -FLT_MAX); + merge_group->ChannelsMask.SetBit(channel_no); + merge_group->ChannelsCount++; + merge_group->ClipRect.Add(src_channel->_CmdBuffer[0].ClipRect); + merge_group_mask |= (1 << merge_group_n); + } + + // Invalidate current draw channel + // (we don't clear DrawChannelFrozen/DrawChannelUnfrozen solely to facilitate debugging/later inspection of data) + column->DrawChannelCurrent = (ImU8)-1; + } + + // [DEBUG] Display merge groups +#if 0 + if (g.IO.KeyShift) + for (int merge_group_n = 0; merge_group_n < IM_ARRAYSIZE(merge_groups); merge_group_n++) + { + MergeGroup* merge_group = &merge_groups[merge_group_n]; + if (merge_group->ChannelsCount == 0) + continue; + char buf[32]; + ImFormatString(buf, 32, "MG%d:%d", merge_group_n, merge_group->ChannelsCount); + ImVec2 text_pos = merge_group->ClipRect.Min + ImVec2(4, 4); + ImVec2 text_size = CalcTextSize(buf, NULL); + GetForegroundDrawList()->AddRectFilled(text_pos, text_pos + text_size, IM_COL32(0, 0, 0, 255)); + GetForegroundDrawList()->AddText(text_pos, IM_COL32(255, 255, 0, 255), buf, NULL); + GetForegroundDrawList()->AddRect(merge_group->ClipRect.Min, merge_group->ClipRect.Max, IM_COL32(255, 255, 0, 255)); + } +#endif + + // 2. Rewrite channel list in our preferred order + if (merge_group_mask != 0) + { + // We skip channel 0 (Bg0) and 1 (Bg1 frozen) from the shuffling since they won't move - see channels allocation in TableUpdateDrawChannels(). + const int LEADING_DRAW_CHANNELS = 2; + g.DrawChannelsTempMergeBuffer.resize(splitter->_Count - LEADING_DRAW_CHANNELS); // Use shared temporary storage so the allocation gets amortized + ImDrawChannel* dst_tmp = g.DrawChannelsTempMergeBuffer.Data; + ImBitArray remaining_mask; // We need 132-bit of storage + remaining_mask.ClearBits(); + remaining_mask.SetBitRange(LEADING_DRAW_CHANNELS, splitter->_Count - 1); + remaining_mask.ClearBit(table->Bg1DrawChannelUnfrozen); + IM_ASSERT(has_freeze_v == false || table->Bg1DrawChannelUnfrozen != TABLE_DRAW_CHANNEL_BG1_FROZEN); + int remaining_count = splitter->_Count - (has_freeze_v ? LEADING_DRAW_CHANNELS + 1 : LEADING_DRAW_CHANNELS); + //ImRect host_rect = (table->InnerWindow == table->OuterWindow) ? table->InnerClipRect : table->HostClipRect; + ImRect host_rect = table->HostClipRect; + for (int merge_group_n = 0; merge_group_n < IM_ARRAYSIZE(merge_groups); merge_group_n++) + { + if (int merge_channels_count = merge_groups[merge_group_n].ChannelsCount) + { + MergeGroup* merge_group = &merge_groups[merge_group_n]; + ImRect merge_clip_rect = merge_group->ClipRect; + + // Extend outer-most clip limits to match those of host, so draw calls can be merged even if + // outer-most columns have some outer padding offsetting them from their parent ClipRect. + // The principal cases this is dealing with are: + // - On a same-window table (not scrolling = single group), all fitting columns ClipRect -> will extend and match host ClipRect -> will merge + // - Columns can use padding and have left-most ClipRect.Min.x and right-most ClipRect.Max.x != from host ClipRect -> will extend and match host ClipRect -> will merge + // FIXME-TABLE FIXME-WORKRECT: We are wasting a merge opportunity on tables without scrolling if column doesn't fit + // within host clip rect, solely because of the half-padding difference between window->WorkRect and window->InnerClipRect. + if ((merge_group_n & 1) == 0 || !has_freeze_h) + merge_clip_rect.Min.x = ImMin(merge_clip_rect.Min.x, host_rect.Min.x); + if ((merge_group_n & 2) == 0 || !has_freeze_v) + merge_clip_rect.Min.y = ImMin(merge_clip_rect.Min.y, host_rect.Min.y); + if ((merge_group_n & 1) != 0) + merge_clip_rect.Max.x = ImMax(merge_clip_rect.Max.x, host_rect.Max.x); + if ((merge_group_n & 2) != 0 && (table->Flags & ImGuiTableFlags_NoHostExtendY) == 0) + merge_clip_rect.Max.y = ImMax(merge_clip_rect.Max.y, host_rect.Max.y); +#if 0 + GetOverlayDrawList()->AddRect(merge_group->ClipRect.Min, merge_group->ClipRect.Max, IM_COL32(255, 0, 0, 200), 0.0f, ~0, 1.0f); + GetOverlayDrawList()->AddLine(merge_group->ClipRect.Min, merge_clip_rect.Min, IM_COL32(255, 100, 0, 200)); + GetOverlayDrawList()->AddLine(merge_group->ClipRect.Max, merge_clip_rect.Max, IM_COL32(255, 100, 0, 200)); +#endif + remaining_count -= merge_group->ChannelsCount; + for (int n = 0; n < IM_ARRAYSIZE(remaining_mask.Storage); n++) + remaining_mask.Storage[n] &= ~merge_group->ChannelsMask.Storage[n]; + for (int n = 0; n < splitter->_Count && merge_channels_count != 0; n++) + { + // Copy + overwrite new clip rect + if (!merge_group->ChannelsMask.TestBit(n)) + continue; + merge_group->ChannelsMask.ClearBit(n); + merge_channels_count--; + + ImDrawChannel* channel = &splitter->_Channels[n]; + IM_ASSERT(channel->_CmdBuffer.Size == 1 && merge_clip_rect.Contains(ImRect(channel->_CmdBuffer[0].ClipRect))); + channel->_CmdBuffer[0].ClipRect = merge_clip_rect.ToVec4(); + memcpy(dst_tmp++, channel, sizeof(ImDrawChannel)); + } + } + + // Make sure Bg1DrawChannelUnfrozen appears in the middle of our groups (whereas Bg0 and Bg1 frozen are fixed to 0 and 1) + if (merge_group_n == 1 && has_freeze_v) + memcpy(dst_tmp++, &splitter->_Channels[table->Bg1DrawChannelUnfrozen], sizeof(ImDrawChannel)); + } + + // Append unmergeable channels that we didn't reorder at the end of the list + for (int n = 0; n < splitter->_Count && remaining_count != 0; n++) + { + if (!remaining_mask.TestBit(n)) + continue; + ImDrawChannel* channel = &splitter->_Channels[n]; + memcpy(dst_tmp++, channel, sizeof(ImDrawChannel)); + remaining_count--; + } + IM_ASSERT(dst_tmp == g.DrawChannelsTempMergeBuffer.Data + g.DrawChannelsTempMergeBuffer.Size); + memcpy(splitter->_Channels.Data + LEADING_DRAW_CHANNELS, g.DrawChannelsTempMergeBuffer.Data, (splitter->_Count - LEADING_DRAW_CHANNELS) * sizeof(ImDrawChannel)); + } +} + //------------------------------------------------------------------------- // [SECTION] Tables: Sorting //-------------------------------------------------------------------------