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Internals: Combo: Extracted into a BeginComboPopup() function. (ocorn…
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…ut#4168)

Renamed frame_bb > bb locally.
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@ocornut
ocornut committed May 28, 2021
1 parent 5b4bc98 commit 060b6ee
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Showing 2 changed files with 54 additions and 36 deletions.
3 changes: 3 additions & 0 deletions imgui_internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2401,6 +2401,9 @@ namespace ImGui
IMGUI_API ImVec2 FindBestWindowPosForPopupEx(const ImVec2& ref_pos, const ImVec2& size, ImGuiDir* last_dir, const ImRect& r_outer, const ImRect& r_avoid, ImGuiPopupPositionPolicy policy);
IMGUI_API bool BeginViewportSideBar(const char* name, ImGuiViewport* viewport, ImGuiDir dir, float size, ImGuiWindowFlags window_flags);

// Combos
IMGUI_API bool BeginComboPopup(ImGuiID popup_id, const ImRect& bb, ImGuiComboFlags flags);

// Gamepad/Keyboard Navigation
IMGUI_API void NavInitWindow(ImGuiWindow* window, bool force_reinit);
IMGUI_API bool NavMoveRequestButNoResultYet();
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87 changes: 51 additions & 36 deletions imgui_widgets.cpp
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Expand Up @@ -1537,7 +1537,9 @@ void ImGui::ShrinkWidths(ImGuiShrinkWidthItem* items, int count, float width_exc
//-------------------------------------------------------------------------
// [SECTION] Widgets: ComboBox
//-------------------------------------------------------------------------
// - CalcMaxPopupHeightFromItemCount() [Internal]
// - BeginCombo()
// - BeginComboPopup() [Internal]
// - EndCombo()
// - Combo()
//-------------------------------------------------------------------------
Expand All @@ -1552,106 +1554,119 @@ static float CalcMaxPopupHeightFromItemCount(int items_count)

bool ImGui::BeginCombo(const char* label, const char* preview_value, ImGuiComboFlags flags)
{
// Always consume the SetNextWindowSizeConstraint() call in our early return paths
ImGuiContext& g = *GImGui;
bool has_window_size_constraint = (g.NextWindowData.Flags & ImGuiNextWindowDataFlags_HasSizeConstraint) != 0;
g.NextWindowData.Flags &= ~ImGuiNextWindowDataFlags_HasSizeConstraint;

ImGuiWindow* window = GetCurrentWindow();

ImGuiNextWindowDataFlags backup_next_window_data_flags = g.NextWindowData.Flags;
g.NextWindowData.ClearFlags(); // We behave like Begin() and need to consume those values
if (window->SkipItems)
return false;

IM_ASSERT((flags & (ImGuiComboFlags_NoArrowButton | ImGuiComboFlags_NoPreview)) != (ImGuiComboFlags_NoArrowButton | ImGuiComboFlags_NoPreview)); // Can't use both flags together

const ImGuiStyle& style = g.Style;
const ImGuiID id = window->GetID(label);
IM_ASSERT((flags & (ImGuiComboFlags_NoArrowButton | ImGuiComboFlags_NoPreview)) != (ImGuiComboFlags_NoArrowButton | ImGuiComboFlags_NoPreview)); // Can't use both flags together

const float arrow_size = (flags & ImGuiComboFlags_NoArrowButton) ? 0.0f : GetFrameHeight();
const ImVec2 label_size = CalcTextSize(label, NULL, true);
const float w = (flags & ImGuiComboFlags_NoPreview) ? arrow_size : CalcItemWidth();
const ImRect frame_bb(window->DC.CursorPos, window->DC.CursorPos + ImVec2(w, label_size.y + style.FramePadding.y * 2.0f));
const ImRect total_bb(frame_bb.Min, frame_bb.Max + ImVec2(label_size.x > 0.0f ? style.ItemInnerSpacing.x + label_size.x : 0.0f, 0.0f));
const ImRect bb(window->DC.CursorPos, window->DC.CursorPos + ImVec2(w, label_size.y + style.FramePadding.y * 2.0f));
const ImRect total_bb(bb.Min, bb.Max + ImVec2(label_size.x > 0.0f ? style.ItemInnerSpacing.x + label_size.x : 0.0f, 0.0f));
ItemSize(total_bb, style.FramePadding.y);
if (!ItemAdd(total_bb, id, &frame_bb))
if (!ItemAdd(total_bb, id, &bb))
return false;

// Open on click
bool hovered, held;
bool pressed = ButtonBehavior(frame_bb, id, &hovered, &held);

bool pressed = ButtonBehavior(bb, id, &hovered, &held);
const ImGuiID popup_id = ImHashStr("##ComboPopup", 0, id);
bool popup_open = IsPopupOpen(popup_id, ImGuiPopupFlags_None);
if ((pressed || g.NavActivateId == id) && !popup_open)
{
OpenPopupEx(popup_id, ImGuiPopupFlags_None);
popup_open = true;
}

// Render shape
const ImU32 frame_col = GetColorU32(hovered ? ImGuiCol_FrameBgHovered : ImGuiCol_FrameBg);
const float value_x2 = ImMax(frame_bb.Min.x, frame_bb.Max.x - arrow_size);
RenderNavHighlight(frame_bb, id);
const float value_x2 = ImMax(bb.Min.x, bb.Max.x - arrow_size);
RenderNavHighlight(bb, id);
if (!(flags & ImGuiComboFlags_NoPreview))
window->DrawList->AddRectFilled(frame_bb.Min, ImVec2(value_x2, frame_bb.Max.y), frame_col, style.FrameRounding, (flags & ImGuiComboFlags_NoArrowButton) ? ImDrawFlags_RoundCornersAll : ImDrawFlags_RoundCornersLeft);
window->DrawList->AddRectFilled(bb.Min, ImVec2(value_x2, bb.Max.y), frame_col, style.FrameRounding, (flags & ImGuiComboFlags_NoArrowButton) ? ImDrawFlags_RoundCornersAll : ImDrawFlags_RoundCornersLeft);
if (!(flags & ImGuiComboFlags_NoArrowButton))
{
ImU32 bg_col = GetColorU32((popup_open || hovered) ? ImGuiCol_ButtonHovered : ImGuiCol_Button);
ImU32 text_col = GetColorU32(ImGuiCol_Text);
window->DrawList->AddRectFilled(ImVec2(value_x2, frame_bb.Min.y), frame_bb.Max, bg_col, style.FrameRounding, (w <= arrow_size) ? ImDrawFlags_RoundCornersAll : ImDrawFlags_RoundCornersRight);
if (value_x2 + arrow_size - style.FramePadding.x <= frame_bb.Max.x)
RenderArrow(window->DrawList, ImVec2(value_x2 + style.FramePadding.y, frame_bb.Min.y + style.FramePadding.y), text_col, ImGuiDir_Down, 1.0f);
window->DrawList->AddRectFilled(ImVec2(value_x2, bb.Min.y), bb.Max, bg_col, style.FrameRounding, (w <= arrow_size) ? ImDrawFlags_RoundCornersAll : ImDrawFlags_RoundCornersRight);
if (value_x2 + arrow_size - style.FramePadding.x <= bb.Max.x)
RenderArrow(window->DrawList, ImVec2(value_x2 + style.FramePadding.y, bb.Min.y + style.FramePadding.y), text_col, ImGuiDir_Down, 1.0f);
}
RenderFrameBorder(frame_bb.Min, frame_bb.Max, style.FrameRounding);
RenderFrameBorder(bb.Min, bb.Max, style.FrameRounding);

// Render preview and label
if (preview_value != NULL && !(flags & ImGuiComboFlags_NoPreview))
{
ImVec2 preview_pos = frame_bb.Min + style.FramePadding;
if (g.LogEnabled)
LogSetNextTextDecoration("{", "}");
RenderTextClipped(preview_pos, ImVec2(value_x2, frame_bb.Max.y), preview_value, NULL, NULL, ImVec2(0.0f, 0.0f));
RenderTextClipped(bb.Min + style.FramePadding, ImVec2(value_x2, bb.Max.y), preview_value, NULL, NULL);
}
if (label_size.x > 0)
RenderText(ImVec2(frame_bb.Max.x + style.ItemInnerSpacing.x, frame_bb.Min.y + style.FramePadding.y), label);

if ((pressed || g.NavActivateId == id) && !popup_open)
{
OpenPopupEx(popup_id, ImGuiPopupFlags_None);
popup_open = true;
}
RenderText(ImVec2(bb.Max.x + style.ItemInnerSpacing.x, bb.Min.y + style.FramePadding.y), label);

if (!popup_open)
return false;

if (has_window_size_constraint)
g.NextWindowData.Flags = backup_next_window_data_flags;
return BeginComboPopup(popup_id, bb, flags);
}

bool ImGui::BeginComboPopup(ImGuiID popup_id, const ImRect& bb, ImGuiComboFlags flags)
{
ImGuiContext& g = *GImGui;
if (!IsPopupOpen(popup_id, ImGuiPopupFlags_None))
{
g.NextWindowData.ClearFlags();
return false;
}

// Set popup size
float w = bb.GetWidth();
if (g.NextWindowData.Flags & ImGuiNextWindowDataFlags_HasSizeConstraint)
{
g.NextWindowData.Flags |= ImGuiNextWindowDataFlags_HasSizeConstraint;
g.NextWindowData.SizeConstraintRect.Min.x = ImMax(g.NextWindowData.SizeConstraintRect.Min.x, w);
}
else
{
if ((flags & ImGuiComboFlags_HeightMask_) == 0)
flags |= ImGuiComboFlags_HeightRegular;
IM_ASSERT(ImIsPowerOfTwo(flags & ImGuiComboFlags_HeightMask_)); // Only one
IM_ASSERT(ImIsPowerOfTwo(flags & ImGuiComboFlags_HeightMask_)); // Only one
int popup_max_height_in_items = -1;
if (flags & ImGuiComboFlags_HeightRegular) popup_max_height_in_items = 8;
else if (flags & ImGuiComboFlags_HeightSmall) popup_max_height_in_items = 4;
else if (flags & ImGuiComboFlags_HeightLarge) popup_max_height_in_items = 20;
SetNextWindowSizeConstraints(ImVec2(w, 0.0f), ImVec2(FLT_MAX, CalcMaxPopupHeightFromItemCount(popup_max_height_in_items)));
}

// This is essentially a specialized version of BeginPopupEx()
char name[16];
ImFormatString(name, IM_ARRAYSIZE(name), "##Combo_%02d", g.BeginPopupStack.Size); // Recycle windows based on depth

// Position the window given a custom constraint (peak into expected window size so we can position it)
// This might be easier to express with an hypothetical SetNextWindowPosConstraints() function.
// Set position given a custom constraint (peak into expected window size so we can position it)
// FIXME: This might be easier to express with an hypothetical SetNextWindowPosConstraints() function?
// FIXME: This might be moved to Begin() or at least around the same spot where Tooltips and other Popups are calling FindBestWindowPosForPopupEx()?
if (ImGuiWindow* popup_window = FindWindowByName(name))
if (popup_window->WasActive)
{
// Always override 'AutoPosLastDirection' to not leave a chance for a past value to affect us.
ImVec2 size_expected = CalcWindowNextAutoFitSize(popup_window);
popup_window->AutoPosLastDirection = (flags & ImGuiComboFlags_PopupAlignLeft) ? ImGuiDir_Left : ImGuiDir_Down; // Left = "Below, Toward Left", Down = "Below, Toward Right (default)"
ImRect r_outer = GetPopupAllowedExtentRect(popup_window);
ImVec2 pos = FindBestWindowPosForPopupEx(frame_bb.GetBL(), size_expected, &popup_window->AutoPosLastDirection, r_outer, frame_bb, ImGuiPopupPositionPolicy_ComboBox);
ImVec2 pos = FindBestWindowPosForPopupEx(bb.GetBL(), size_expected, &popup_window->AutoPosLastDirection, r_outer, bb, ImGuiPopupPositionPolicy_ComboBox);
SetNextWindowPos(pos);
}

// We don't use BeginPopupEx() solely because we have a custom name string, which we could make an argument to BeginPopupEx()
ImGuiWindowFlags window_flags = ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_Popup | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_NoMove;

// Horizontally align ourselves with the framed text
PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(style.FramePadding.x, style.WindowPadding.y));
PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(g.Style.FramePadding.x, g.Style.WindowPadding.y)); // Horizontally align ourselves with the framed text
bool ret = Begin(name, NULL, window_flags);
PopStyleVar();
if (!ret)
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