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Added CalcListClipping() helper.

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ocornut 2015-02-08 13:44:09 +00:00
parent 29e0aad739
commit 9e3f8adfac
2 changed files with 41 additions and 1 deletions
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41
imgui.cpp
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@ -604,7 +604,8 @@ static inline float ImMin(float lhs, float rhs)
static inline float ImMax(float lhs, float rhs) { return lhs >= rhs ? lhs : rhs; }
static inline ImVec2 ImMin(const ImVec2& lhs, const ImVec2& rhs) { return ImVec2(ImMin(lhs.x,rhs.x), ImMin(lhs.y,rhs.y)); }
static inline ImVec2 ImMax(const ImVec2& lhs, const ImVec2& rhs) { return ImVec2(ImMax(lhs.x,rhs.x), ImMax(lhs.y,rhs.y)); }
static inline float ImClamp(float f, float mn, float mx) { return (f < mn) ? mn : (f > mx) ? mx : f; }
static inline int ImClamp(int v, int mn, int mx) { return (v < mn) ? mn : (v > mx) ? mx : v; }
static inline float ImClamp(float v, float mn, float mx) { return (v < mn) ? mn : (v > mx) ? mx : v; }
static inline ImVec2 ImClamp(const ImVec2& f, const ImVec2& mn, ImVec2 mx) { return ImVec2(ImClamp(f.x,mn.x,mx.x), ImClamp(f.y,mn.y,mx.y)); }
static inline float ImSaturate(float f) { return (f < 0.0f) ? 0.0f : (f > 1.0f) ? 1.0f : f; }
static inline float ImLerp(float a, float b, float t) { return a + (b - a) * t; }
@ -2174,6 +2175,44 @@ ImVec2 ImGui::CalcTextSize(const char* text, const char* text_end, bool hide_tex
return text_size;
}
// Helper to calculate clipping of large list of evenly sized items.
// If you are displaying thousands of items and you have a random access to the list, you can perform clipping yourself to save on CPU.
// {
// float item_height = ImGui::GetTextLineHeightWithSpacing();
// int display_start, display_end;
// ImGui::CalcListClipping(count, item_height, &display_start, &display_end); // calculate how many to clip/display
// ImGui::SetCursorPosY(ImGui::GetCursorPosY() + (display_start) * item_height); // advance cursor
// for (int i = display_start; i < display_end; i++) // display only visible items
// // TODO: display visible item
// ImGui::SetCursorPosY(ImGui::GetCursorPosY() + (count - display_end) * item_height); // advance cursor
// }
void ImGui::CalcListClipping(int items_count, float items_height, int* out_items_display_start, int* out_items_display_end)
{
ImGuiState& g = *GImGui;
ImGuiWindow* window = GetCurrentWindow();
if (g.LogEnabled)
{
// If logging is active, do not perform any clipping
*out_items_display_start = 0;
*out_items_display_end = items_count;
return;
}
const ImVec2 pos = window->DC.CursorPos;
const ImVec4 clip_rect = window->ClipRectStack.back();
const float clip_y1 = clip_rect.y;
const float clip_y2 = clip_rect.w;
int start = (int)((clip_y1 - pos.y) / items_height);
int end = (int)((clip_y2 - pos.y) / items_height);
start = ImClamp(start, 0, items_count);
end = ImClamp(end + 1, start, items_count);
*out_items_display_start = start;
*out_items_display_end = end;
}
// Find window given position, search front-to-back
static ImGuiWindow* FindHoveredWindow(ImVec2 pos, bool excluding_childs)
{

1
imgui.h
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@ -331,6 +331,7 @@ namespace ImGui
IMGUI_API int GetFrameCount();
IMGUI_API const char* GetStyleColName(ImGuiCol idx);
IMGUI_API ImVec2 CalcTextSize(const char* text, const char* text_end = NULL, bool hide_text_after_double_hash = false, float wrap_width = -1.0f);
IMGUI_API void CalcListClipping(int items_count, float items_height, int* out_items_display_start, int* out_items_display_end); // helper to manually clip large list of items. see comments in implementation.
IMGUI_API ImU32 ColorConvertFloat4ToU32(const ImVec4& in);
IMGUI_API void ColorConvertRGBtoHSV(float r, float g, float b, float& out_h, float& out_s, float& out_v);