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engines/ags/shared/font/ags_font_renderer.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef AGS_SHARED_FONT_AGS_FONT_RENDERER_H
+#define AGS_SHARED_FONT_AGS_FONT_RENDERER_H
+
+#include "common/std/utility.h"
+#include "ags/shared/core/types.h"
+#include "ags/shared/util/string.h"
+
+namespace AGS3 {
+
+class BITMAP;
+
+class IAGSFontRenderer {
+public:
+	virtual bool LoadFromDisk(int fontNumber, int fontSize) = 0;
+	virtual void FreeMemory(int fontNumber) = 0;
+	virtual bool SupportsExtendedCharacters(int fontNumber) = 0;
+	virtual int GetTextWidth(const char *text, int fontNumber) = 0;
+	// Get actual height of the given line of text
+	virtual int GetTextHeight(const char *text, int fontNumber) = 0;
+	virtual void RenderText(const char *text, int fontNumber, BITMAP *destination, int x, int y, int colour) = 0;
+	virtual void AdjustYCoordinateForFont(int *ycoord, int fontNumber) = 0;
+	virtual void EnsureTextValidForFont(char *text, int fontNumber) = 0;
+protected:
+	IAGSFontRenderer() {}
+	~IAGSFontRenderer() {}
+};
+
+// Extended font renderer interface.
+// WARNING: this interface is exposed for plugins and declared for the second time in agsplugin.h
+class IAGSFontRenderer2 : public IAGSFontRenderer {
+public:
+	// Returns engine API version this font renderer complies to.
+	// Must not be lower than 26 (this interface was added at API v26).
+	virtual int GetVersion() = 0;
+	// Returns an arbitrary renderer name; this is for informational
+	// purposes only.
+	virtual const char *GetRendererName() = 0;
+	// Returns given font's name (if available).
+	virtual const char *GetFontName(int fontNumber) = 0;
+	// Returns the given font's height: that is the maximal vertical size
+	// that the font glyphs may occupy.
+	virtual int GetFontHeight(int fontNumber) = 0;
+	// Returns the given font's linespacing;
+	// is allowed to return 0, telling that no specific linespacing
+	// is assigned for this font.
+	virtual int GetLineSpacing(int fontNumber) = 0;
+
+protected:
+	IAGSFontRenderer2() {}
+	~IAGSFontRenderer2() {}
+};
+
+// Font render params, mainly for dealing with various compatibility issues.
+struct FontRenderParams {
+	// Font's render multiplier
+	int SizeMultiplier = 1;
+	int LoadMode = 0; // contains font flags from FFLG_LOADMODEMASK
+};
+
+// Describes loaded font's properties
+struct FontMetrics {
+	// Nominal font's height, equals to the game-requested size of the font.
+	// This may or not be equal to font's face height; sometimes a font cannot
+	// be scaled exactly to particular size, and then nominal height appears different
+	// (usually - smaller) than the real one.
+	int NominalHeight = 0;
+	// Real font's height, equals to reported ascender + descender.
+	// This is what you normally think as a font's height.
+	int RealHeight = 0;
+	// Compatible height, equals to either NominalHeight or RealHeight,
+	// selected depending on the game settings.
+	// This property is used in calculating linespace, etc.
+	int CompatHeight = 0;
+	// Maximal vertical extent of a font (top; bottom), this tells the actual
+	// graphical bounds that may be occupied by font's glyphs.
+	// In a "proper" font this extent is (0; RealHeight-1), but "bad" fonts may
+	// have individual glyphs exceeding these bounds, in both directions.
+	// Note that "top" may be negative!
+	std::pair<int, int> VExtent;
+
+	inline int ExtentHeight() const { return VExtent.second - VExtent.first; }
+};
+
+// The strictly internal font renderer interface, not to use in plugin API.
+// Contains methods necessary for built-in font renderers.
+class IAGSFontRendererInternal : public IAGSFontRenderer2 {
+public:
+	// Tells if this is a bitmap font (otherwise it's a vector font)
+	virtual bool IsBitmapFont() = 0;
+	// Load font, applying extended font rendering parameters
+	virtual bool LoadFromDiskEx(int fontNumber, int fontSize, AGS::Shared::String *src_filename,
+								const FontRenderParams *params, FontMetrics *metrics) = 0;
+	// Fill FontMetrics struct; note that it may be left cleared if this is not supported
+	virtual void GetFontMetrics(int fontNumber, FontMetrics *metrics) = 0;
+	// Perform any necessary adjustments when the AA mode is toggled
+	virtual void AdjustFontForAntiAlias(int fontNumber, bool aa_mode) = 0;
+
+protected:
+	IAGSFontRendererInternal() {}
+	~IAGSFontRendererInternal() {}
+};
+
+} // namespace AGS3
+
+#endif