From a9e31a3db5dbebd072ff186282ac291be43e3354 Mon Sep 17 00:00:00 2001 From: Rudolf Polzer Date: Tue, 16 Nov 2010 14:07:06 +0100 Subject: [PATCH] glfont.cpp: add an internal class that uses Pango --- libs/gtkutil/glfont.cpp | 139 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+) diff --git a/libs/gtkutil/glfont.cpp b/libs/gtkutil/glfont.cpp index d2d3b87..962f3fe 100644 --- a/libs/gtkutil/glfont.cpp +++ b/libs/gtkutil/glfont.cpp @@ -157,3 +157,142 @@ void glfont_release(GLFont& font) font = GLFont(0, 0, 0, 0); } #endif + + + +// new font code ripped from ZeroRadiant (not in use yet) + +#include +#include "igl.h" + +class GLFontInternal +{ + const char *font_string; + int font_height; + int font_ascent; + int font_descent; + int y_offset_bitmap_render_pango_units; + PangoContext *ft2_context; + + public: + GLFontInternal(const char *_font_string): font_string(font_string) + { + PangoFontDescription *font_desc; + PangoLayout *layout; + PangoRectangle log_rect; + int font_ascent_pango_units; + int font_descent_pango_units; + + // This call is deprecated so we'll have to fix it sometime. + ft2_context = pango_ft2_get_context(72, 72); + + font_desc = pango_font_description_from_string(font_string); + pango_context_set_font_description(ft2_context, font_desc); + pango_font_description_free(font_desc); + + layout = pango_layout_new(ft2_context); +#if !PANGO_VERSION_CHECK(1,22,0) + PangoLayoutIter *iter; + iter = pango_layout_get_iter(layout); + font_ascent_pango_units = pango_layout_iter_get_baseline(iter); + pango_layout_iter_free(iter); +#else + font_ascent_pango_units = pango_layout_get_baseline(layout); +#endif + pango_layout_get_extents(layout, NULL, &log_rect); + g_object_unref(G_OBJECT(layout)); + font_descent_pango_units = log_rect.height - font_ascent_pango_units; + + font_ascent = PANGO_PIXELS_CEIL(font_ascent_pango_units); + font_descent = PANGO_PIXELS_CEIL(font_descent_pango_units); + font_height = font_ascent + font_descent; + y_offset_bitmap_render_pango_units = (font_ascent * PANGO_SCALE) - font_ascent_pango_units; + } + + ~GLFontInternal() + { + g_object_unref(G_OBJECT(ft2_context)); + } + + // Renders the input text at the current location with the current color. + // The X position of the current location is used to place the left edge of the text image, + // where the text image bounds are defined as the logical extents of the line of text. + // The Y position of the current location is used to place the bottom of the text image. + // You should offset the Y position by the amount returned by gtk_glwidget_font_descent() + // if you want to place the baseline of the text image at the current Y position. + // Note: A problem with this function is that if the lower left corner of the text falls + // just a hair outside of the viewport (meaning the current raster position is invalid), + // then no text will be rendered. The solution to this is a very hacky one. You can search + // Google for "glDrawPixels clipping". + void printString(const char *s) + { + // The idea for this code initially came from the font-pangoft2.c example that comes with GtkGLExt. + + PangoLayout *layout; + PangoRectangle log_rect; + FT_Bitmap bitmap; + unsigned char *begin_bitmap_buffer; + GLfloat color[4]; + GLint previous_unpack_alignment; + GLboolean previous_blend_enabled; + GLint previous_blend_func_src; + GLint previous_blend_func_dst; + GLfloat previous_red_bias; + GLfloat previous_green_bias; + GLfloat previous_blue_bias; + GLfloat previous_alpha_scale; + + layout = pango_layout_new(ft2_context); + pango_layout_set_width(layout, -1); // -1 no wrapping. All text on one line. + pango_layout_set_text(layout, s, -1); // -1 null-terminated string. + pango_layout_get_extents(layout, NULL, &log_rect); + + if (log_rect.width > 0 && log_rect.height > 0) { + bitmap.rows = font_ascent + font_descent; + bitmap.width = PANGO_PIXELS_CEIL(log_rect.width); + bitmap.pitch = -bitmap.width; // Rendering it "upside down" for OpenGL. + begin_bitmap_buffer = (unsigned char *) g_malloc(bitmap.rows * bitmap.width); + memset(begin_bitmap_buffer, 0, bitmap.rows * bitmap.width); + bitmap.buffer = begin_bitmap_buffer + (bitmap.rows - 1) * bitmap.width; // See pitch above. + bitmap.num_grays = 0xff; + bitmap.pixel_mode = FT_PIXEL_MODE_GRAY; + pango_ft2_render_layout_subpixel(&bitmap, layout, -log_rect.x, + y_offset_bitmap_render_pango_units); + GlobalOpenGL().m_glGetFloatv(GL_CURRENT_COLOR, color); + + // Save state. I didn't see any OpenGL push/pop operations for these. + // Question: Is saving/restoring this state necessary? Being safe. + GlobalOpenGL().m_glGetIntegerv(GL_UNPACK_ALIGNMENT, &previous_unpack_alignment); + previous_blend_enabled = GlobalOpenGL().m_glIsEnabled(GL_BLEND); + GlobalOpenGL().m_glGetIntegerv(GL_BLEND_SRC, &previous_blend_func_src); + GlobalOpenGL().m_glGetIntegerv(GL_BLEND_DST, &previous_blend_func_dst); + GlobalOpenGL().m_glGetFloatv(GL_RED_BIAS, &previous_red_bias); + GlobalOpenGL().m_glGetFloatv(GL_GREEN_BIAS, &previous_green_bias); + GlobalOpenGL().m_glGetFloatv(GL_BLUE_BIAS, &previous_blue_bias); + GlobalOpenGL().m_glGetFloatv(GL_ALPHA_SCALE, &previous_alpha_scale); + + GlobalOpenGL().m_glPixelStorei(GL_UNPACK_ALIGNMENT, 1); + GlobalOpenGL().m_glEnable(GL_BLEND); + GlobalOpenGL().m_glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); + GlobalOpenGL().m_glPixelTransferf(GL_RED_BIAS, color[0]); + GlobalOpenGL().m_glPixelTransferf(GL_GREEN_BIAS, color[1]); + GlobalOpenGL().m_glPixelTransferf(GL_BLUE_BIAS, color[2]); + GlobalOpenGL().m_glPixelTransferf(GL_ALPHA_SCALE, color[3]); + + GlobalOpenGL().m_glDrawPixels(bitmap.width, bitmap.rows, + GL_ALPHA, GL_UNSIGNED_BYTE, begin_bitmap_buffer); + g_free(begin_bitmap_buffer); + + // Restore state in reverse order of how we set it. + GlobalOpenGL().m_glPixelTransferf(GL_ALPHA_SCALE, previous_alpha_scale); + GlobalOpenGL().m_glPixelTransferf(GL_BLUE_BIAS, previous_blue_bias); + GlobalOpenGL().m_glPixelTransferf(GL_GREEN_BIAS, previous_green_bias); + GlobalOpenGL().m_glPixelTransferf(GL_RED_BIAS, previous_red_bias); + GlobalOpenGL().m_glBlendFunc(previous_blend_func_src, previous_blend_func_dst); + if (!previous_blend_enabled) { GlobalOpenGL().m_glDisable(GL_BLEND); } + GlobalOpenGL().m_glPixelStorei(GL_UNPACK_ALIGNMENT, previous_unpack_alignment); + } + + g_object_unref(G_OBJECT(layout)); + } +}; -- 2.39.2