diff --git a/imgui_demo.cpp b/imgui_demo.cpp index aa6ecf010..45b758436 100644 --- a/imgui_demo.cpp +++ b/imgui_demo.cpp @@ -9634,6 +9634,15 @@ struct ExampleAssetsBrowser bool RequestSort = false; // Deferred sort request float ZoomWheelAccum = 0.0f; // Mouse wheel accumulator to handle smooth wheels better + // Calculated sizes for layout, output of UpdateLayoutSizes(). Could be locals but our code is simpler this way. + ImVec2 LayoutItemSize; + ImVec2 LayoutItemStep; // == LayoutItemSize + LayoutItemSpacing + float LayoutItemSpacing = 0.0f; + float LayoutSelectableSpacing = 0.0f; + float LayoutOuterPadding = 0.0f; + int LayoutColumnCount = 0; + int LayoutLineCount = 0; + // Functions ExampleAssetsBrowser() { @@ -9654,6 +9663,29 @@ struct ExampleAssetsBrowser Selection.Clear(); } + // Logic would be written in the main code BeginChild() and outputing to local variables. + // We extracted it into a function so we can call it easily from multiple places. + void UpdateLayoutSizes(float avail_width) + { + // Layout: when not stretching: allow extending into right-most spacing. + LayoutItemSpacing = (float)IconSpacing; + if (StretchSpacing == false) + avail_width += floorf(LayoutItemSpacing * 0.5f); + + // Layout: calculate number of icon per line and number of lines + LayoutItemSize = ImVec2(floorf(IconSize), floorf(IconSize)); + LayoutColumnCount = IM_MAX((int)(avail_width / (LayoutItemSize.x + LayoutItemSpacing)), 1); + LayoutLineCount = (Items.Size + LayoutColumnCount - 1) / LayoutColumnCount; + + // Layout: when stretching: allocate remaining space to more spacing. Round before division, so item_spacing may be non-integer. + if (StretchSpacing && LayoutColumnCount > 1) + LayoutItemSpacing = floorf(avail_width - LayoutItemSize.x * LayoutColumnCount) / LayoutColumnCount; + + LayoutItemStep = ImVec2(LayoutItemSize.x + LayoutItemSpacing, LayoutItemSize.y + LayoutItemSpacing); + LayoutSelectableSpacing = IM_MAX(floorf(LayoutItemSpacing) - IconHitSpacing, 0.0f); + LayoutOuterPadding = floorf(LayoutItemSpacing * 0.5f); + } + void Draw(const char* title, bool* p_open) { ImGui::SetNextWindowSize(ImVec2(IconSize * 25, IconSize * 15), ImGuiCond_FirstUseEver); @@ -9722,27 +9754,18 @@ struct ExampleAssetsBrowser } ImGui::PopStyleVar(); - if (ImGui::BeginChild("Assets", ImVec2(0, -ImGui::GetTextLineHeightWithSpacing()), true, ImGuiWindowFlags_NoMove)) + ImGuiIO& io = ImGui::GetIO(); + ImGui::SetNextWindowContentSize(ImVec2(0.0f, LayoutOuterPadding + LayoutLineCount * (LayoutItemSize.x + LayoutItemSpacing))); + if (ImGui::BeginChild("Assets", ImVec2(0.0f, -ImGui::GetTextLineHeightWithSpacing()), ImGuiChildFlags_Border, ImGuiWindowFlags_NoMove)) { ImDrawList* draw_list = ImGui::GetWindowDrawList(); - const ImVec2 item_size(floorf(IconSize), floorf(IconSize)); - // Layout: when not stretching: allow extending into right-most spacing. - float item_spacing = (float)IconSpacing; - const float avail_width = ImGui::GetContentRegionAvail().x + (StretchSpacing ? 0.0f : floorf(item_spacing * 0.5f)); - - // Layout: calculate number of icon per line and number of lines - const int column_count = IM_MAX((int)(avail_width / (item_size.x + IconSpacing)), 1); - const int line_count = (Items.Size + column_count - 1) / column_count; - - // Layout: when stretching: allocate remaining space to more spacing. Round before division, so item_spacing may be non-integer. - if (StretchSpacing && column_count > 1) - item_spacing = floorf(avail_width - item_size.x * column_count) / column_count; + const float avail_width = ImGui::GetContentRegionAvail().x; + UpdateLayoutSizes(avail_width); // Calculate and store start position. - const float outer_padding = floorf(item_spacing * 0.5f); ImVec2 start_pos = ImGui::GetCursorScreenPos(); - start_pos = ImVec2(start_pos.x + outer_padding, start_pos.y + outer_padding); + start_pos = ImVec2(start_pos.x + LayoutOuterPadding, start_pos.y + LayoutOuterPadding); ImGui::SetCursorScreenPos(start_pos); // Multi-select @@ -9760,22 +9783,22 @@ struct ExampleAssetsBrowser const int item_curr_idx_to_focus = want_delete ? Selection.ApplyDeletionPreLoop(ms_io, Items.Size) : -1; RequestDelete = false; - // Altering ItemSpacing may seem unnecessary as we position every items using SetCursorScreenPos()... + // Push LayoutSelectableSpacing (which is LayoutItemSpacing minus hit-spacing, if we decide to have hit gaps between items) + // Altering style ItemSpacing may seem unnecessary as we position every items using SetCursorScreenPos()... // But it is necessary for two reasons: // - Selectables uses it by default to visually fill the space between two items. // - The vertical spacing would be measured by Clipper to calculate line height if we didn't provide it explicitly (here we do). - const float selectable_spacing = IM_MAX(floorf(item_spacing) - IconHitSpacing, 0.0f); - ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(selectable_spacing, selectable_spacing)); + ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(LayoutSelectableSpacing, LayoutSelectableSpacing)); // Rendering parameters const ImU32 icon_bg_color = IM_COL32(48, 48, 48, 128); const ImU32 icon_type_overlay_colors[3] = { 0, IM_COL32(200, 70, 70, 255), IM_COL32(70, 170, 70, 255) }; const ImVec2 icon_type_overlay_size = ImVec2(4.0f, 4.0f); - const bool display_label = (item_size.x >= ImGui::CalcTextSize("999").x); + const bool display_label = (LayoutItemSize.x >= ImGui::CalcTextSize("999").x); - const float line_height = item_size.y + item_spacing; + const int column_count = LayoutColumnCount; ImGuiListClipper clipper; - clipper.Begin(line_count, line_height); + clipper.Begin(LayoutLineCount, LayoutItemStep.y); if (item_curr_idx_to_focus != -1) clipper.IncludeItemByIndex(item_curr_idx_to_focus / column_count); // Ensure focused item line is not clipped. if (ms_io->RangeSrcItem != -1) @@ -9792,17 +9815,17 @@ struct ExampleAssetsBrowser ImGui::PushID((int)item_data->ID); // Position item - ImVec2 pos = ImVec2(start_pos.x + (item_idx % column_count) * (item_size.x + item_spacing), start_pos.y + (line_idx * line_height)); + ImVec2 pos = ImVec2(start_pos.x + (item_idx % column_count) * LayoutItemStep.x, start_pos.y + line_idx * LayoutItemStep.y); ImGui::SetCursorScreenPos(pos); // Draw box ImVec2 box_min(pos.x - 1, pos.y - 1); - ImVec2 box_max(box_min.x + item_size.x + 2, box_min.y + item_size.y + 2); + ImVec2 box_max(box_min.x + LayoutItemSize.x + 2, box_min.y + LayoutItemSize.y + 2); draw_list->AddRect(box_min, box_max, IM_COL32(90, 90, 90, 255)); ImGui::SetNextItemSelectionUserData(item_idx); bool item_is_selected = Selection.Contains((ImGuiID)item_data->ID); - ImGui::Selectable("", item_is_selected, ImGuiSelectableFlags_None, item_size); + ImGui::Selectable("", item_is_selected, ImGuiSelectableFlags_None, LayoutItemSize); // Update our selection state immediately (without waiting for EndMultiSelect() requests) // because we use this to alter the color of our text/icon. @@ -9865,25 +9888,40 @@ struct ExampleAssetsBrowser // FIXME-MULTISELECT: Find a way to expose this in public API. This currently requires "imgui_internal.h" //ImGui::NavMoveRequestTryWrapping(ImGui::GetCurrentWindow(), ImGuiNavMoveFlags_WrapX); - } - // Zooming with CTRL+Wheel - // FIXME-MULTISELECT: Try to maintain scroll. - ImGuiIO& io = ImGui::GetIO(); - if (ImGui::IsWindowAppearing()) - ZoomWheelAccum = 0.0f; - if (ImGui::IsWindowHovered() && io.MouseWheel != 0.0f && ImGui::IsKeyDown(ImGuiMod_Ctrl) && ImGui::IsAnyItemActive() == false) - { - ZoomWheelAccum += io.MouseWheel; - if (fabsf(ZoomWheelAccum) >= 1.0f) + // Zooming with CTRL+Wheel + if (ImGui::IsWindowAppearing()) + ZoomWheelAccum = 0.0f; + if (ImGui::IsWindowHovered() && io.MouseWheel != 0.0f && ImGui::IsKeyDown(ImGuiMod_Ctrl) && ImGui::IsAnyItemActive() == false) { - IconSize *= powf(1.1f, (float)(int)ZoomWheelAccum); - IconSize = IM_CLAMP(IconSize, 16.0f, 128.0f); - ZoomWheelAccum -= (int)ZoomWheelAccum; + ZoomWheelAccum += io.MouseWheel; + if (fabsf(ZoomWheelAccum) >= 1.0f) + { + // Calculate hovered item index from mouse location + // FIXME: Locking aiming on 'hovered_item_idx' (with a cool-down timer) would ensure zoom keeps on it. + const float hovered_item_nx = (io.MousePos.x - start_pos.x + LayoutItemSpacing * 0.5f) / LayoutItemStep.x; + const float hovered_item_ny = (io.MousePos.y - start_pos.y + LayoutItemSpacing * 0.5f) / LayoutItemStep.y; + const int hovered_item_idx = ((int)hovered_item_ny * LayoutColumnCount) + (int)hovered_item_nx; + //ImGui::SetTooltip("%f,%f -> item %d", hovered_item_nx, hovered_item_ny, hovered_item_idx); // Move those 4 lines in block above for easy debugging + + // Zoom + IconSize *= powf(1.1f, (float)(int)ZoomWheelAccum); + IconSize = IM_CLAMP(IconSize, 16.0f, 128.0f); + ZoomWheelAccum -= (int)ZoomWheelAccum; + UpdateLayoutSizes(avail_width); + + // Manipulate scroll to that we will land at the same Y location of currently hovered item. + // - Calculate next frame position of item under mouse + // - Set new scroll position to be used in next ImGui::BeginChild() call. + float hovered_item_rel_pos_y = ((float)(hovered_item_idx / LayoutColumnCount) + fmodf(hovered_item_ny, 1.0f)) * LayoutItemStep.y; + hovered_item_rel_pos_y += ImGui::GetStyle().WindowPadding.y; + float mouse_local_y = io.MousePos.y - ImGui::GetWindowPos().y; + ImGui::SetScrollY(hovered_item_rel_pos_y - mouse_local_y); + } } } - ImGui::EndChild(); + ImGui::Text("Selected: %d/%d items", Selection.Size, Items.Size); ImGui::End(); }