Card10 Framebuffer Library

Preamble

Copyright (C) 2020 Frank Abelbeck <frank.abelbeck@googlemail.com>

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/>.

Description

Collection of routines for manipulation of a card10 badge framebuffer.

General l0dable Installation Routine

1. Get the card10 repo and set-up the toolchain (depends on your OS). Let's assume the local firmware repo lies at "$FIRMWARE"
2. Create a new directory PROGNAME below "$FIRMWARE/l0dables".
3. Copy the specified files to said directory "$FIRMWARE/l0dables/PROGNAME/". Copy "meson.PROGNAME.build" as "meson.build" to this directory.

4. Edit "meson.build" in the directory "$FIRMWARE/l0dables" and add the following line:

   subdir('PROGNAME/')

5. Compile the firmware; this will now build the newly included l0dable, too:

   cd $FIRMWARE ninja -C build/

6. Mount card10 badge (assuming mountpoint "$MEDIACARD10").

7. If not yet done: Create file "card10.cfg" in card10's root directory and add the following line to it:

   execute_elf = true

8. Copy "$FIRMWARE/build/l0dables/DIRNAME/PROGNAME.elf" to "$MEDIACARD10/apps". The App "PROGNAME.elf" should now be available in the card10 menu.

Installation of the surfacedemo l0dable

Follow general installation instructions as stated above. Modify and extend them as follows.

2. Use PROGNAME=surfacedemo

3. Files to copy:

   surfacedemo.c, faFramebuffer.c, faFramebuffer.h, faReadPng.c, faReadPng.h faSurfaceBase.c, faSurfaceBase.h, faSurface.c, faSurface.h, faSurfacePP.c, faSurfacePP.h

4. Create a directory "$MEDIACARD10/png/" (if not yet existent) and copy the following images to it:

   sprite-logo.png, sprite.png, stars.png, text.png, title.png

Installation of the triangledemo l0dable

Follow general installation instructions as stated above. Modify and extend them as follows.

2. Use PROGNAME=triangledemo

3. Files to copy:

   triangledemo.c, faFramebuffer.c, faFramebuffer.h, faReadPng.c, faReadPng.h faSurfaceBase.c, faSurfaceBase.h, faSurface.c, faSurface.h

4. Create a directory "$MEDIACARD10/png/" (if not yet existent) and copy the following image to it:

   stars.png

Installation of the fontdemo l0dable

Follow general installation instructions as stated above. Modify and extend them as follows.

2. Use PROGNAME=fontdemo

3. Files to copy:

   fontdemo.c, faFramebuffer.c, faFramebuffer.h, faSurfaceBase.c, faSurfaceBase.h, faSurface.c, faSurface.h, faReadPng.h, faReadPng.c, faFontFile.h, faFontFile.c

4. Create a directory "$MEDIACARD10/png/" (if not yet existent) and copy the following files to it:

   faTinyFont.bin, earthrise.png

Changelog

2020-03-22

release of fontdemo

2020-03-11

revised toolchain for faFontFile handling: merged into one program faFFTool.py faFontFile format creation now done via "faFFTool.py create" (image-based symbol definition + text file code mapping) faFontFile format checking now done via "faFFTool.py check" faFontFile format rendering now possible via "faFFTool.py render"

2020-03-07

bitmap font library reaches beta state

2020-03-06

bitmap font library reaches alpha state

2020-02-17

created triangledemo

2020-02-14

implemented disc (untested)

2020-02-12

implemented triangle and rectangle changed meaning of return value bounding box: now not clipped to surface (mask tracks modifications) simplified normalisation/denormalisation in integer math: shifts instead of divs and muls

2020-02-06

changed SurfaceMod to an even simpler format because processing mask pixels took longer than simply redrawing the display :(

2020-02-05

changed SurfaceMod to a simpler format reduced size of width/height to uint8_t (limiting images to 255*255, ok for card10's screen)

2020-02-03

introduced SurfaceMod: a surface modification data structure for directed surface updates introduced first drawing functions for primitives (point, line, circle, arc) code refactoring: function naming now follows convention ObjectAction()

2020-01-20

introduced boundingBoxSprite parameter; finally the crawling text works; preparing faSurface lib for release

2020-01-16

solution works, without perspective projection (assuming last row of matrix is 0,0,1); starting work on general surface library (faSurfacePP)

2020-01-13

try other way 'round: parameter "matrix" and "matrixInverse"

• calculate surface bounding box with matrix
• iteratore over surface coordinates of the bounding box
• calculate p = A^-1 * p', i.e. get sprite coordinates and paint surface coordinates accordingly

2020-01-12:

solution works, but shows non-interpolation pattern

2020-01-09

move from "3 shears" to "general affine transformation", i.e. p' = A*p problem: interpolation; anti-aliasing/interpolation via blendFractional() does not work

2019-12-25

surface library supports stretching and scaling (nearest-neighbour interpol)

2019-12-23

surface library supports shearing, rotating, mirroring

2019-12-15

moved image and pixel structures into separate faSurface library PNG images now always have an alpha channel created Surface management library faSurface created framebuffer management library faFramebuffer dug-out 80s papers from Porter, Duff, Paeth (image composition + rotation)

2019-12-01

made pngdata and image dynamically allocated; checked heap memory usage with valgrind; git repo init; decision to develop a l0dable instead of a MicroPython module (use GPL3 license, avoid dealing with the MicroPython C layer)

2019-11-19

readPng.c ready for release.