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Added a separate end-of-text cluster
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This allows moving the cursor past a newline at the end of the text.
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@slouken
slouken committed Oct 7, 2024
1 parent a01f973 commit aebd2d2
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Showing 2 changed files with 41 additions and 29 deletions.
2 changes: 1 addition & 1 deletion examples/editbox.c
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Original file line number Diff line number Diff line change
Expand Up @@ -456,7 +456,7 @@ void EditBox_Draw(EditBox *edit)

static int GetCursorTextIndex(TTF_Font *font, int x, const TTF_SubString *substring)
{
if (substring->flags & TTF_SUBSTRING_LINE_END) {
if (substring->flags & (TTF_SUBSTRING_LINE_END | TTF_SUBSTRING_TEXT_END)) {
return substring->offset;
}

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68 changes: 40 additions & 28 deletions src/SDL_ttf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3724,10 +3724,11 @@ static int SDLCALL SortClusters(const void *a, const void *b)
return (A->offset - B->offset);
}

static int CalculateClusterLengths(TTF_Font *font, TTF_SubString *clusters, int num_clusters, size_t length, int *lines)
static int CalculateClusterLengths(TTF_Text *text, TTF_SubString *clusters, int num_clusters, size_t length, int *lines)
{
SDL_qsort(clusters, num_clusters, sizeof(*clusters), SortClusters);

TTF_Font *font = text->internal->font;
int i;
const TTF_SubString *src = clusters;
TTF_SubString *last = NULL;
Expand Down Expand Up @@ -3769,13 +3770,28 @@ static int CalculateClusterLengths(TTF_Font *font, TTF_SubString *clusters, int
cluster->rect.x += cluster->rect.w;
cluster->rect.w = 0;
}
} else if (cluster->flags & TTF_SUBSTRING_TEXT_END) {
if (last) {
if (last->length > 0 && text->text[last->offset + last->length - 1] == '\n') {
cluster->line_index = last->line_index + 1;
cluster->rect.y = (cluster->line_index * font->lineskip);
cluster->rect.h = font->height;
} else {
cluster->line_index = last->line_index;
SDL_copyp(&cluster->rect, &last->rect);
cluster->rect.x += cluster->rect.w;
cluster->rect.w = 0;
}
} else {
cluster->rect.h = font->height;
}
}

if (i < (num_clusters - 1)) {
cluster->length = clusters[i + 1].offset - cluster->offset;
} else {
cluster->flags |= TTF_SUBSTRING_TEXT_END;
cluster->length = (int)(length - cluster->offset);
SDL_assert(cluster->flags & TTF_SUBSTRING_TEXT_END);
SDL_assert(cluster->offset == length);
}
last = cluster;
}
Expand Down Expand Up @@ -3810,7 +3826,7 @@ static bool LayoutText(TTF_Text *text)
goto done;
}

clusters = (TTF_SubString *)SDL_calloc(font->num_clusters + 1, sizeof(*clusters));
clusters = (TTF_SubString *)SDL_calloc(font->num_clusters + 2, sizeof(*clusters));
if (!clusters) {
goto done;
}
Expand All @@ -3819,10 +3835,15 @@ static bool LayoutText(TTF_Text *text)
if (!Render_Line_TextEngine(font, xstart, ystart, width, height, ops, &num_ops, clusters, &num_clusters, 0, 0)) {
goto done;
}

cluster = &clusters[num_clusters++];
cluster->flags = TTF_SUBSTRING_LINE_END;
cluster->offset = (int)SDL_strlen(text->text);

cluster = &clusters[num_clusters++];
cluster->flags = TTF_SUBSTRING_TEXT_END;
cluster->offset = (int)SDL_strlen(text->text);

// Apply underline or strikethrough style, if needed
if (TTF_HANDLE_STYLE_UNDERLINE(font)) {
Draw_Line_TextEngine(font, width, height, 0, ystart + font->underline_top_row, width, font->line_thickness, ops, &num_ops);
Expand All @@ -3832,7 +3853,7 @@ static bool LayoutText(TTF_Text *text)
Draw_Line_TextEngine(font, width, height, 0, ystart + font->strikethrough_top_row, width, font->line_thickness, ops, &num_ops);
}

num_clusters = CalculateClusterLengths(font, clusters, num_clusters, length, NULL);
num_clusters = CalculateClusterLengths(text, clusters, num_clusters, length, NULL);

result = true;

Expand Down Expand Up @@ -3862,7 +3883,7 @@ static bool LayoutTextWrapped(TTF_Text *text)
TTF_DrawOperation *ops = NULL, *new_ops;
int num_ops = 0, max_ops = 0, extra_ops = 0, additional_ops;
TTF_SubString *clusters = NULL, *new_clusters, *cluster;
int num_clusters = 0, max_clusters = 0, additional_clusters, cluster_offset;
int num_clusters = 0, max_clusters = 0, cluster_offset;
int *lines = NULL;
bool result = false;

Expand All @@ -3887,20 +3908,18 @@ static bool LayoutTextWrapped(TTF_Text *text)
}
}

max_clusters = numLines + 1;
clusters = (TTF_SubString *)SDL_calloc(max_clusters, sizeof(*clusters));
if (!clusters) {
goto done;
}

// Render each line
for (i = 0; i < numLines; i++) {
int xstart, ystart, line_width, xoffset;

if (strLines[i].length == 0) {
new_clusters = (TTF_SubString *)SDL_realloc(clusters, (max_clusters + 1) * sizeof(*new_clusters));
if (!new_clusters) {
goto done;
}
clusters = new_clusters;
max_clusters += 1;

cluster = &clusters[num_clusters++];
SDL_zerop(cluster);
cluster->flags = TTF_SUBSTRING_LINE_END;
cluster->offset = (int)(uintptr_t)(strLines[i].text - text->text);
cluster->line_index = i;
Expand Down Expand Up @@ -3936,14 +3955,13 @@ static bool LayoutTextWrapped(TTF_Text *text)
max_ops += additional_ops;

// Allocate space for the clusters on this line
additional_clusters = (font->num_clusters + 1);
new_clusters = (TTF_SubString *)SDL_realloc(clusters, (max_clusters + additional_clusters) * sizeof(*new_clusters));
new_clusters = (TTF_SubString *)SDL_realloc(clusters, (max_clusters + font->num_clusters) * sizeof(*new_clusters));
if (!new_clusters) {
goto done;
}
SDL_memset(new_clusters + max_clusters, 0, additional_clusters * sizeof(*new_clusters));
SDL_memset(new_clusters + max_clusters, 0, font->num_clusters * sizeof(*new_clusters));
clusters = new_clusters;
max_clusters += additional_clusters;
max_clusters += font->num_clusters;
cluster_offset = (int)(uintptr_t)(strLines[i].text - text->text);

// Create the text drawing operations
Expand All @@ -3964,8 +3982,11 @@ static bool LayoutTextWrapped(TTF_Text *text)
Draw_Line_TextEngine(font, width, height, xoffset, ystart + font->strikethrough_top_row, line_width, font->line_thickness, ops, &num_ops);
}
}
cluster = &clusters[num_clusters++];
cluster->flags = TTF_SUBSTRING_TEXT_END;
cluster->offset = (int)length;

num_clusters = CalculateClusterLengths(font, clusters, num_clusters, length, lines);
num_clusters = CalculateClusterLengths(text, clusters, num_clusters, length, lines);

result = true;

Expand Down Expand Up @@ -4293,9 +4314,6 @@ bool TTF_GetTextSubString(TTF_Text *text, int offset, TTF_SubString *substring)
int length = (int)SDL_strlen(text->text);
if (offset >= length) {
SDL_copyp(substring, &clusters[num_clusters - 1]);
substring->length = 0;
substring->rect.x += substring->rect.w;
substring->rect.w = 0;
return true;
}

Expand Down Expand Up @@ -4366,9 +4384,6 @@ bool TTF_GetTextSubStringForLine(TTF_Text *text, int line, TTF_SubString *substr

if (line >= text->num_lines) {
SDL_copyp(substring, &clusters[num_clusters - 1]);
substring->length = 0;
substring->rect.x += substring->rect.w;
substring->rect.w = 0;
return true;
}

Expand Down Expand Up @@ -4630,9 +4645,6 @@ bool TTF_GetNextTextSubString(TTF_Text *text, const TTF_SubString *substring, TT
}
if (substring->cluster_index == (num_clusters - 1)) {
SDL_copyp(next, &clusters[num_clusters - 1]);
next->length = 0;
next->rect.x += next->rect.w;
next->rect.w = 0;
} else {
SDL_copyp(next, &clusters[substring->cluster_index + 1]);
}
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