Attachment 36336 Details for Bug 28583 – Sample C program that reproduces the glyph_path() PDF problem

Sample C program that reproduces the glyph_path() PDF problem

halo_test.c (text/x-csrc), 5.47 KB, created by Ian Britten on 2010-06-17 08:13:38 UTC

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Creator: Ian Britten

Created: 2010-06-17 08:13:38 UTC

Size: 5.47 KB

patch

obsolete

>#include <cairo/cairo.h>
>#include <cairo/cairo-pdf.h>
>#include <cairo/cairo-ft.h>
>
>#include <ft2build.h>
>#include FT_FREETYPE_H
>
>// This test demonstrates the drawing of a 'halo' around (under) a glyph
>// and a possible PDF problem that occurs.  (cairo 1.8.6)
>// It mimics a workflow of exporting an on-screen rendering to two
>// separate outputs:
>// 1) A high-resolution image of the current on-screen canvas, with the
>//    same shape, etc.
>// 2) A Letter sized PDF, with the current on-screen contents centred on
>//    the page.
>// For both cases, the only a single glyph is rendered, as that is enough
>// to demonstrate the problem
>//
>// The actual problem is that when the PDF output is viewed (Acroread, GV),
>// the glyph is not centred over the glyph_path() that was used to draw
>// the halo.  Note that the problem seems to be worse for tiny text, as
>// in this test.
>// The generated image appears correct.
>//
>// Build with:
>// gcc -std=c99 -g `pkg-config --cflags --libs cairo` halo_test.c
>int main(int argc, char *argv[])
>{
>        const size_t numSurfaces = 2;
>        cairo_surface_t* surfaces[numSurfaces];
>        cairo_t* contexts[numSurfaces];
>
>        // Make the image surface (2400dpi version of  on-screen canvas)
>        cairo_surface_t *imgSurface;
>        cairo_t *imgContext;
>        {
>                const int pixWidth = 18162;
>                const int pixHeight = 13954;
>
>                surfaces[0] = imgSurface = cairo_image_surface_create(
>                        CAIRO_FORMAT_RGB24, pixWidth, pixHeight);
>                contexts[0] = imgContext = cairo_create(imgSurface);
>
>                const double xMinUser = -0.43342314456263187;
>                const double yMinUser = -0.050809551161048683;
>                const double xMaxUser = 1.1822151445626319;
>                const double yMaxUser = 1.1904973911610486;
>
>                const double userWidth = xMaxUser - xMinUser;
>                const double userHeight = yMaxUser - yMinUser;
>                const double scaleX = pixWidth / userWidth; // 11241.377
>                const double scaleY = pixHeight / userHeight; // 11241.377
>
>                cairo_translate(imgContext, 0, pixHeight);
>                cairo_scale(imgContext, scaleX, -scaleY);
>                cairo_translate(imgContext, -xMinUser, -yMinUser);
>        }
>
>        // Make the PDF surface (On-screen canvas fit to 8.5x11 Letter)
>        cairo_surface_t *pdfSurface;
>        cairo_t *pdfContext;
>        {
>                const char fileName[] = "output.pdf";
>                const double pntWidth = 612;
>                const double pntHeight = 791;
>
>                surfaces[1] = pdfSurface = cairo_pdf_surface_create(
>                        fileName, pntWidth, pntHeight);
>                contexts[1] = pdfContext = cairo_create(pdfSurface);
>
>                const double xMinUser = -0.43338089600000007;
>                const double yMinUser = -0.47419451911111121;
>                const double xMaxUser = 1.182172896;
>                const double yMaxUser = 1.6138823591111113;
>
>                const double userWidth = xMaxUser - xMinUser;
>                const double userHeight = yMaxUser - yMinUser;
>                const double scaleX = pntWidth / userWidth; // 11241.377
>                const double scaleY = pntHeight / userHeight; // 11241.377
>
>                cairo_translate(pdfContext, 0, pntHeight);
>                cairo_scale(pdfContext, scaleX, -scaleY);
>                cairo_translate(pdfContext, -xMinUser, -yMinUser);
>        }
>
>        // Get face
>        FT_Library ftLib;
>        FT_Init_FreeType(&ftLib);
>        FT_Face ftFace;
>        FT_New_Face(ftLib, "/usr/share/fonts/msttcorefonts/arial.ttf",
>                    0, &ftFace);
>        cairo_font_face_t *cFace = cairo_ft_font_face_create_for_ft_face(
>                ftFace, 0);
>
>        // Font info
>        const double userSize = 0.0030594270330026917;
>        cairo_matrix_t fMatrix;
>        cairo_matrix_init_scale(&fMatrix, userSize, -userSize);
>
>        // Glyph info
>        cairo_glyph_t glyphs[1];
>        glyphs[0].index = 27;
>        glyphs[0].x = 0.37439600000000001; // Centre of output (Both cases)
>        glyphs[0].y = 0.56984391999999995; // Centre of output (Both cases)
>
>        // Draw to each of the surfaces
>        for (size_t i=0; i<numSurfaces; ++i)
>        {
>                cairo_surface_t *currS = surfaces[i];
>                cairo_t *currC = contexts[i];
>
>                // Set the font matrix, face, 
>                cairo_set_font_matrix(currC, &fMatrix);
>                cairo_set_font_face(currC, cFace);
>
>                // Start by drawing the halo
>                cairo_glyph_path(currC, glyphs, 1);
>                cairo_set_source_rgba(currC, 0.0, 0.5, 1.0, 1.0);
>                cairo_set_line_width(currC, 0.00030594270330026933);
>                cairo_set_line_join(currC, CAIRO_LINE_JOIN_ROUND);
>                cairo_set_line_cap(currC, CAIRO_LINE_CAP_SQUARE);
>                cairo_stroke(currC);
>
>                // Draw the glyph
>                cairo_set_source_rgba(currC, 0.0, 0.0, 0.0, 1.0);
>                cairo_show_glyphs(currC, glyphs, 1);
>        }
>
>        // Save out the contents and cleanup
>        cairo_surface_write_to_png(imgSurface, "output.png");
>        cairo_destroy(imgContext);
>        cairo_destroy(pdfContext);
>        cairo_surface_destroy(imgSurface);
>        cairo_surface_destroy(pdfSurface);
>        cairo_font_face_destroy(cFace);
>
>        FT_Done_Face(ftFace);
>        FT_Done_FreeType(ftLib);
>
>        cairo_debug_reset_static_data(); // Valgrind
>
>        return 0;
>}

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Attachments on bug 28583: 36336 | 36337 | 36338

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