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InputTextMultiline() painfully merged most computation passes into on…
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…e, better clipping, much faster for large text (#200)
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@ocornut
ocornut committed Jun 19, 2015
1 parent 84987ac commit 73db855
Showing 1 changed file with 80 additions and 26 deletions.
106 changes: 80 additions & 26 deletions imgui.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -551,8 +551,9 @@ static void CloseInactivePopups();
// Helpers: String
static int ImStricmp(const char* str1, const char* str2);
static int ImStrnicmp(const char* str1, const char* str2, int count);
static char* ImStrdup(const char *str);
static char* ImStrdup(const char* str);
static size_t ImStrlenW(const ImWchar* str);
static const ImWchar* ImStrbolW(const ImWchar* buf_mid_line, const ImWchar* buf_begin); // Find beginning-of-line
static const char* ImStristr(const char* haystack, const char* needle, const char* needle_end);
static size_t ImFormatString(char* buf, size_t buf_size, const char* fmt, ...);
static size_t ImFormatStringV(char* buf, size_t buf_size, const char* fmt, va_list args);
Expand Down Expand Up @@ -786,6 +787,13 @@ static size_t ImStrlenW(const ImWchar* str)
return n;
}

static const ImWchar* ImStrbolW(const ImWchar* buf_mid_line, const ImWchar* buf_begin) // find beginning-of-line
{
while (buf_mid_line > buf_begin && buf_mid_line[-1] != '\n')
buf_mid_line--;
return buf_mid_line;
}

static const char* ImStristr(const char* haystack, const char* needle, const char* needle_end)
{
if (!needle_end)
Expand Down Expand Up @@ -7102,26 +7110,64 @@ static bool InputTextEx(const char* label, char* buf, size_t buf_size, const ImV
ImVec2 text_size(0.f, 0.f);
if (g.ActiveId == id || (edit_state.Id == id && is_multiline && g.ActiveId == draw_window->GetID("#SCROLLY")))
{
ImVec2 render_scroll = ImVec2((edit_state.Id == id) ? edit_state.ScrollX : 0.0f, 0.0f);
edit_state.CursorAnim += g.IO.DeltaTime;

// 1. Display the text (this can be more easily clipped)
// 2. Handle scrolling, highlight selection, display cursor: those all requires some form of 1d->2d cursor position calculation, which we will try to merge to minimize the cost.
ImVec2 cursor_offset;
InputTextCalcTextSizeW(edit_state.Text.begin(), edit_state.Text.begin() + edit_state.StbState.cursor, NULL, &cursor_offset);
// We need to:
// - Display the text (this can be more easily clipped)
// - Handle scrolling, highlight selection, display cursor (those all requires some form of 1d->2d cursor position calculation)
// - Measure text height (for scrollbar)
// We are attempting to do most of that in one main pass to minimize the computation cost (non-negligible for large amount of text) + 2nd pass for selection rendering (we could merge them by an extra refactoring effort)
const ImWchar* text_begin = edit_state.Text.begin();
const ImWchar* text_end = text_begin + edit_state.CurLenW;
ImVec2 cursor_offset, select_start_offset;

{
// Count lines + find lines numbers of cursor and select_start
int matches_remaining = 0;
int matches_line_no[2] = { -1, -999 };
const ImWchar* matches_ptr[2];
matches_ptr[0] = text_begin + edit_state.StbState.cursor; matches_remaining++;
if (edit_state.StbState.select_start != edit_state.StbState.select_end)
{
matches_ptr[1] = text_begin + ImMin(edit_state.StbState.select_start, edit_state.StbState.select_end);
matches_line_no[1] = -1;
matches_remaining++;
}
matches_remaining += is_multiline ? 1 : 0; // So that we never exit the loop until all lines are counted.

if (is_multiline)
text_size = InputTextCalcTextSizeW(edit_state.Text.begin(), edit_state.Text.begin() + edit_state.CurLenW);
int line_count = 0;
for (const ImWchar* s = text_begin; s < text_end+1; s++)
if ((*s) == '\n' || s == text_end)
{
line_count++;
if (matches_line_no[0] == -1 && s >= matches_ptr[0]) { matches_line_no[0] = line_count; if (--matches_remaining <= 0) break; }
if (matches_line_no[1] == -1 && s >= matches_ptr[1]) { matches_line_no[1] = line_count; if (--matches_remaining <= 0) break; }
}

// Calculate 2d position
IM_ASSERT(matches_line_no[0] != -1);
cursor_offset.x = InputTextCalcTextSizeW(ImStrbolW(matches_ptr[0], text_begin), matches_ptr[0]).x;
cursor_offset.y = matches_line_no[0] * g.FontSize;
if (matches_line_no[1] >= 0)
{
select_start_offset.x = InputTextCalcTextSizeW(ImStrbolW(matches_ptr[1], text_begin), matches_ptr[1]).x;
select_start_offset.y = matches_line_no[1] * g.FontSize;
}

// Calculate text height
if (is_multiline)
text_size = ImVec2(size.x, line_count * g.FontSize);
}

// Scroll
if (edit_state.CursorFollow)
{
// Horizontal scroll in chunks of quarter width
const float scroll_increment_x = size.x * 0.25f;
if (cursor_offset.x < edit_state.ScrollX)
render_scroll.x = edit_state.ScrollX = ImMax(0.0f, cursor_offset.x - scroll_increment_x);
edit_state.ScrollX = ImMax(0.0f, cursor_offset.x - scroll_increment_x);
else if (cursor_offset.x - size.x >= edit_state.ScrollX)
render_scroll.x = edit_state.ScrollX = cursor_offset.x - size.x + scroll_increment_x;
edit_state.ScrollX = cursor_offset.x - size.x + scroll_increment_x;

// Vertical scroll
if (is_multiline)
Expand All @@ -7137,38 +7183,46 @@ static bool InputTextEx(const char* label, char* buf, size_t buf_size, const ImV
}
}
edit_state.CursorFollow = false;
ImVec2 render_scroll = ImVec2(edit_state.ScrollX, 0.0f);

// Draw selection
int select_begin_idx = edit_state.StbState.select_start;
int select_end_idx = edit_state.StbState.select_end;
if (select_begin_idx != select_end_idx)
if (edit_state.StbState.select_start != edit_state.StbState.select_end)
{
// FIXME-OPT
ImWchar* text_selected_begin = edit_state.Text.begin() + ImMin(select_begin_idx,select_end_idx);
ImWchar* text_selected_end = edit_state.Text.begin() + ImMax(select_begin_idx,select_end_idx);
ImVec2 rect_pos;
InputTextCalcTextSizeW(edit_state.Text.begin(), text_selected_begin, NULL, &rect_pos);
const ImWchar* text_selected_begin = text_begin + ImMin(edit_state.StbState.select_start, edit_state.StbState.select_end);
const ImWchar* text_selected_end = text_begin + ImMax(edit_state.StbState.select_start, edit_state.StbState.select_end);

float bg_offy_up = is_multiline ? 0.0f : -1.0f; // FIXME: those offsets should be part of the style? they don't play so well with multi-line selection.
float bg_offy_dn = is_multiline ? 0.0f : 2.0f;
ImU32 bg_color = draw_window->Color(ImGuiCol_TextSelectedBg);
ImVec2 rect_pos = render_pos + select_start_offset - render_scroll;
for (const ImWchar* p = text_selected_begin; p < text_selected_end; )
{
ImVec2 rect_size = InputTextCalcTextSizeW(p, text_selected_end, &p, NULL, true);
if (rect_size.x <= 0.0f) rect_size.x = (float)(int)(g.Font->GetCharAdvance((unsigned short)' ') * 0.50f); // So we can see selected empty lines
ImRect rect(render_pos - render_scroll + rect_pos + ImVec2(0.0f, bg_offy_up - g.FontSize), render_pos - render_scroll + rect_pos + ImVec2(rect_size.x, bg_offy_dn));
rect.Clip(clip_rect);
if (rect.Overlaps(clip_rect))
draw_window->DrawList->AddRectFilled(rect.Min, rect.Max, bg_color);
rect_pos.x = 0.0f;
if (rect_pos.y > clip_rect.w + g.FontSize)
break;
if (rect_pos.y < clip_rect.y)
{
while (p < text_selected_end)
if (*p++ == '\n')
break;
}
else
{
ImVec2 rect_size = InputTextCalcTextSizeW(p, text_selected_end, &p, NULL, true);
if (rect_size.x <= 0.0f) rect_size.x = (float)(int)(g.Font->GetCharAdvance((unsigned short)' ') * 0.50f); // So we can see selected empty lines
ImRect rect(rect_pos + ImVec2(0.0f, bg_offy_up - g.FontSize), rect_pos +ImVec2(rect_size.x, bg_offy_dn));
rect.Clip(clip_rect);
if (rect.Overlaps(clip_rect))
draw_window->DrawList->AddRectFilled(rect.Min, rect.Max, bg_color);
}
rect_pos.x = render_pos.x - render_scroll.x;
rect_pos.y += g.FontSize;
}
}

draw_window->DrawList->AddText(g.Font, g.FontSize, render_pos - render_scroll, draw_window->Color(ImGuiCol_Text), buf, buf+edit_state.CurLenA, 0.0f, is_multiline ? NULL : &clip_rect);

// Draw blinking cursor
ImVec2 cursor_screen_pos = render_pos + cursor_offset - ImVec2(edit_state.ScrollX, 0.0f);
ImVec2 cursor_screen_pos = render_pos + cursor_offset - render_scroll;
if (g.InputTextState.CursorIsVisible())
draw_window->DrawList->AddLine(cursor_screen_pos + ImVec2(0,-g.FontSize+1), cursor_screen_pos + ImVec2(0,-1), window->Color(ImGuiCol_Text));

Expand Down

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