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Add text alignment support, fix wrapping behavior

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This refactors the semantics of Font::CalcWordWrapA - it had several subtle issues that rendered the line_width unsuitable for external use.
Now returns the location of the first line break, and the length of the line including any leading whitespace.

This PR refactors the implementation of and implements RenderText and CalcTextSize wrapping in terms of CalcWordWrapPositionA.
This commit is contained in:
Webster Sheets
2021-06-21 02:46:21 -04:00
committed by Drezil
parent d07649b7b4
commit 8bcb0cda73
5 changed files with 55 additions and 28 deletions
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55
imgui_draw.cpp
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@ -1569,7 +1569,7 @@ void ImDrawList::AddBezierQuadratic(const ImVec2& p1, const ImVec2& p2, const Im
PathStroke(col, 0, thickness);
}
void ImDrawList::AddText(const ImFont* font, float font_size, const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end, float wrap_width, const ImVec4* cpu_fine_clip_rect)
void ImDrawList::AddText(const ImFont* font, float font_size, const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end, float wrap_width, float text_align, const ImVec4* cpu_fine_clip_rect)
{
if ((col & IM_COL32_A_MASK) == 0)
return;
@ -1595,7 +1595,7 @@ void ImDrawList::AddText(const ImFont* font, float font_size, const ImVec2& pos,
clip_rect.z = ImMin(clip_rect.z, cpu_fine_clip_rect->z);
clip_rect.w = ImMin(clip_rect.w, cpu_fine_clip_rect->w);
}
font->RenderText(this, font_size, pos, col, clip_rect, text_begin, text_end, wrap_width, cpu_fine_clip_rect != NULL);
font->RenderText(this, font_size, pos, col, clip_rect, text_begin, text_end, wrap_width, text_align, cpu_fine_clip_rect != NULL);
}
void ImDrawList::AddText(const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end)
@ -3418,7 +3418,7 @@ static inline const char* CalcWordWrapNextLineStartA(const char* text, const cha
// Simple word-wrapping for English, not full-featured. Please submit failing cases!
// This will return the next location to wrap from. If no wrapping if necessary, this will fast-forward to e.g. text_end.
// FIXME: Much possible improvements (don't cut things like "word !", "word!!!" but cut within "word,,,,", more sensible support for punctuations, support for Unicode punctuations, etc.)
const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const char* text_end, float wrap_width) const
const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const char* text_end, float wrap_width, float *line_length) const
{
// For references, possible wrap point marked with ^
// "aaa bbb, ccc,ddd. eee fff. ggg!"
@ -3434,6 +3434,7 @@ const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const c
float line_width = 0.0f;
float word_width = 0.0f;
float blank_width = 0.0f;
float last_blank_width = 0.0f;
wrap_width /= scale; // We work with unscaled widths to avoid scaling every characters
const char* word_end = text;
@ -3455,10 +3456,9 @@ const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const c
{
if (c == '\n')
{
line_width = word_width = blank_width = 0.0f;
inside_word = true;
s = next_s;
continue;
line_width += word_width;
word_width = last_blank_width = 0.0f;
break;
}
if (c == '\r')
{
@ -3472,7 +3472,6 @@ const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const c
{
if (inside_word)
{
line_width += blank_width;
blank_width = 0.0f;
word_end = s;
}
@ -3481,7 +3480,6 @@ const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const c
}
else
{
word_width += char_width;
if (inside_word)
{
word_end = next_s;
@ -3490,8 +3488,10 @@ const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const c
{
prev_word_end = word_end;
line_width += word_width + blank_width;
last_blank_width = blank_width;
word_width = blank_width = 0.0f;
}
word_width += char_width;
// Allow wrapping after punctuation.
inside_word = (c != '.' && c != ',' && c != ';' && c != '!' && c != '?' && c != '\"');
@ -3500,9 +3500,12 @@ const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const c
// We ignore blank width at the end of the line (they can be skipped)
if (line_width + word_width > wrap_width)
{
// Words that cannot possibly fit within an entire line will be cut anywhere.
if (word_width < wrap_width)
s = prev_word_end ? prev_word_end : word_end;
// Words that cannot possibly fit within an entire line will be cut before
// the character that pushed them over the limit.
else
line_width += word_width - char_width;
break;
}
@ -3513,6 +3516,14 @@ const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const c
// +1 may not be a character start point in UTF-8 but it's ok because caller loops use (text >= word_wrap_eol).
if (s == text && text < text_end)
return s + 1;
if (s == text_end)
line_width += word_width;
else
line_width -= last_blank_width;
if (line_length)
*line_length = line_width * scale;
return s;
}
@ -3526,6 +3537,7 @@ ImVec2 ImFont::CalcTextSizeA(float size, float max_width, float wrap_width, cons
ImVec2 text_size = ImVec2(0, 0);
float line_width = 0.0f;
float wrapped_line_width = 0.0f;
const bool word_wrap_enabled = (wrap_width > 0.0f);
const char* word_wrap_eol = NULL;
@ -3537,12 +3549,15 @@ ImVec2 ImFont::CalcTextSizeA(float size, float max_width, float wrap_width, cons
{
// Calculate how far we can render. Requires two passes on the string data but keeps the code simple and not intrusive for what's essentially an uncommon feature.
if (!word_wrap_eol)
word_wrap_eol = CalcWordWrapPositionA(scale, s, text_end, wrap_width - line_width);
{
word_wrap_eol = CalcWordWrapPositionA(scale, s, text_end, wrap_width, &wrapped_line_width);
if (word_wrap_eol == s) // Wrap_width is too small to fit anything. Force displaying 1 character to minimize the height discontinuity.
word_wrap_eol++; // +1 may not be a character start point in UTF-8 but it's ok because we use s >= word_wrap_eol below
}
if (s >= word_wrap_eol)
{
if (text_size.x < line_width)
text_size.x = line_width;
text_size.x = ImMax(text_size.x, wrapped_line_width);
text_size.y += line_height;
line_width = 0.0f;
word_wrap_eol = NULL;
@ -3610,7 +3625,7 @@ void ImFont::RenderChar(ImDrawList* draw_list, float size, const ImVec2& pos, Im
}
// Note: as with every ImDrawList drawing function, this expects that the font atlas texture is bound.
void ImFont::RenderText(ImDrawList* draw_list, float size, const ImVec2& pos, ImU32 col, const ImVec4& clip_rect, const char* text_begin, const char* text_end, float wrap_width, bool cpu_fine_clip) const
void ImFont::RenderText(ImDrawList* draw_list, float size, const ImVec2& pos, ImU32 col, const ImVec4& clip_rect, const char* text_begin, const char* text_end, float wrap_width, float text_align, bool cpu_fine_clip) const
{
if (!text_end)
text_end = text_begin + strlen(text_begin); // ImGui:: functions generally already provides a valid text_end, so this is merely to handle direct calls.
@ -3676,13 +3691,21 @@ void ImFont::RenderText(ImDrawList* draw_list, float size, const ImVec2& pos, Im
const ImU32 col_untinted = col | ~IM_COL32_A_MASK;
const char* word_wrap_eol = NULL;
float line_width = 0.0f;
while (s < text_end)
{
if (word_wrap_enabled)
{
// Calculate how far we can render. Requires two passes on the string data but keeps the code simple and not intrusive for what's essentially an uncommon feature.
if (!word_wrap_eol)
word_wrap_eol = CalcWordWrapPositionA(scale, s, text_end, wrap_width - (x - start_x));
{
word_wrap_eol = CalcWordWrapPositionA(scale, s, text_end, wrap_width, &line_width);
if (word_wrap_eol == s) // Wrap_width is too small to fit anything. Force displaying 1 character to minimize the height discontinuity.
word_wrap_eol++; // +1 may not be a character start point in UTF-8 but it's ok because we use s >= word_wrap_eol below
else
x = pos.x + IM_ROUND((wrap_width - line_width) * text_align);
}
if (s >= word_wrap_eol)
{
@ -3703,7 +3726,7 @@ void ImFont::RenderText(ImDrawList* draw_list, float size, const ImVec2& pos, Im
if (c < 32)
{
if (c == '\n')
if (c == '\n') // if word-wrap is disabled, need to break lines manually
{
x = start_x;
y += line_height;