Andrew Kesterson
17e6e04c79
akbasic needs the advance width of one character cell to build a terminal-style
text surface, and the wrapped size to know where a string crosses the right
margin. akgl_text_measure and akgl_text_measure_wrapped report both over
TTF_GetStringSize and TTF_GetStringSizeWrapped; neither needs a renderer, so
this half of the text subsystem is testable without the offscreen harness.
A negative wrap length is refused with AKERR_OUTOFBOUNDS: SDL_ttf reads it as a
very large unsigned width and quietly stops wrapping, which would return a
measurement that is wrong rather than an error the caller can see.
Also fixes akgl_text_loadfont, which checked name twice and passed an unchecked
filepath to TTF_OpenFont (TODO item 39).
The fixture font is a 10 KB monospaced ASCII subset of Liberation Mono, renamed
because "Liberation" is a Reserved Font Name; see
tests/assets/akgl_test_mono.LICENSE.txt. Monospaced so the suite can assert
width("AAAA") == 4 * width("A") rather than hardcode glyph metrics.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
73 lines
3.3 KiB
C
73 lines
3.3 KiB
C
/**
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* @file text.h
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* @brief Declares the public text API.
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*/
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#ifndef _TEXT_H_
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#define _TEXT_H_
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#include <SDL3/SDL.h>
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#include <SDL3_ttf/SDL_ttf.h>
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#include <akerror.h>
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/**
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* @brief Text loadfont.
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* @param name Registry key or human-readable object name.
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* @param filepath Path to the requested file.
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* @param size Requested font size.
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* @return `NULL` on success, otherwise an error context owned by the caller.
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* @throws AKERR_KEY When the corresponding validation or operation fails.
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* @throws AKERR_NULLPOINTER When the corresponding validation or operation fails.
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* @throws AKGL_ERR_SDL When the corresponding validation or operation fails.
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*/
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akerr_ErrorContext AKERR_NOIGNORE *akgl_text_loadfont(char *name, char *filepath, int size);
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/**
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* @brief Text rendertextat.
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* @param font Font used to render the text.
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* @param text UTF-8 text to render.
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* @param color Text color.
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* @param wraplength Maximum rendered line width; zero disables wrapping.
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* @param x Horizontal destination coordinate.
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* @param y Vertical destination coordinate.
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* @return `NULL` on success, otherwise an error context owned by the caller.
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* @throws AKERR_NULLPOINTER When the corresponding validation or operation fails.
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*/
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akerr_ErrorContext AKERR_NOIGNORE *akgl_text_rendertextat(TTF_Font *font, char *text, SDL_Color color, int wraplength, int x, int y);
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/**
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* @brief Report the size, in pixels, that @p text would occupy on one line.
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*
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* Nothing is drawn and no renderer is required. A caller building a character
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* grid measures one cell with this -- the advance width of a single glyph in a
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* monospaced font -- and derives the rest of the grid from it.
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*
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* @param font Font used to render the text.
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* @param text UTF-8 text to measure.
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* @param w Output destination populated with the rendered width in pixels.
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* @param h Output destination populated with the rendered height in pixels.
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* @return `NULL` on success, otherwise an error context owned by the caller.
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* @throws AKERR_NULLPOINTER When the corresponding validation or operation fails.
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* @throws AKGL_ERR_SDL When the corresponding validation or operation fails.
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*/
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akerr_ErrorContext AKERR_NOIGNORE *akgl_text_measure(TTF_Font *font, char *text, int *w, int *h);
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/**
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* @brief Report the size, in pixels, that @p text would occupy when wrapped.
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*
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* The companion to akgl_text_measure() for the wrapping case, matching the
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* @p wraplength argument akgl_text_rendertextat() already takes: a string
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* longer than @p wraplength reports the height of every line it breaks onto.
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* A @p wraplength of zero wraps only on newlines in @p text.
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*
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* @param font Font used to render the text.
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* @param text UTF-8 text to measure.
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* @param wraplength Maximum rendered line width; zero wraps on newlines only.
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* @param w Output destination populated with the rendered width in pixels.
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* @param h Output destination populated with the rendered height in pixels.
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* @return `NULL` on success, otherwise an error context owned by the caller.
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* @throws AKERR_NULLPOINTER When the corresponding validation or operation fails.
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* @throws AKERR_OUTOFBOUNDS When the corresponding validation or operation fails.
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* @throws AKGL_ERR_SDL When the corresponding validation or operation fails.
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*/
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akerr_ErrorContext AKERR_NOIGNORE *akgl_text_measure_wrapped(TTF_Font *font, char *text, int wraplength, int *w, int *h);
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#endif // _TEXT_H_
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