Difference between revisions of "Pixmaps"
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=== Virtual display === | === Virtual display === | ||
| − | + | ''gdispPixmapCreate()'' returns a ''GDisplay'' pointer. Hence the pixmap can be treated like a regular display and all the [[GDISP]] operations (including orientations) can be used on a pixmap. | |
=== Frame buffer surface === | === Frame buffer surface === | ||
| − | + | The memory of a created pixmap can be accessed directly in order to use it like a regular frame buffer surface. ''gdispPixmapGetBits()'' returns a pointer to the first pixel of the pixmap. | |
== Example == | == Example == | ||
Revision as of 15:17, 3 July 2015
Pixmaps provide dynamic frame buffers. A pixmap of any size can by dynamically created and destroyed during runtime. A pixmap represents itself as a virtual display to the user. Hence a pixmap can be treated like a regular display and all the available GDISP drawing routines can be performed inside the pixmap frame buffer. A pixmap can be rendered at any location of a real display at any time.
Contents
API reference
The API reference of the pixmap can be found here.
Creating and destroying a pixmap
Pixmaps can be created and destroyed at any time during runtime using gdispPixmapCreate() and gdispPixmapDelete().
Accessing the pixmap
A pixmap can be treated as either a virtual display or as a memory frame buffer surface.
Virtual display
gdispPixmapCreate() returns a GDisplay pointer. Hence the pixmap can be treated like a regular display and all the GDISP operations (including orientations) can be used on a pixmap.
Frame buffer surface
The memory of a created pixmap can be accessed directly in order to use it like a regular frame buffer surface. gdispPixmapGetBits() returns a pointer to the first pixel of the pixmap.
Example
The following example will show how to create a pixmap and access it both as a virtual display and as a frame buffer surface. Once the pixmap is created it will be blitted incrementally across the entire screen (The pixmap will move across the screen).
#include "gfx.h" #define PIXMAP_WIDTH 40 #define PIXMAP_HEIGHT 10 static GDisplay* pixmap; static pixel_t* surface; int main(void) { coord_t width, height; coord_t i, j; // Initialize and clear the display gfxInit(); // Get the screen size width = gdispGetWidth(); height = gdispGetHeight(); // Create a pixmap and get a pointer to the bits pixmap = gdispPixmapCreate(PIXMAP_WIDTH, PIXMAP_HEIGHT); surface = gdispPixmapGetBits(pixmap); // A pixmap can be treated either as a virtual display or as a memory framebuffer surface. // We demonstrate writing to it using both methods. // First demo drawing onto the surface directly for(j = 0; j < PIXMAP_HEIGHT; j++) for(i = 0; i < PIXMAP_WIDTH; i++) surface[j*PIXMAP_WIDTH + i] = RGB2COLOR(0, 255-i*(256/PIXMAP_WIDTH), j*(256/PIXMAP_HEIGHT)); // Secondly, show drawing a line on it like a virtual display gdispGDrawLine(pixmap, 0, 0, gdispGGetWidth(pixmap)-1, gdispGGetHeight(pixmap)-1, White); i = j = 0; while(TRUE) { // Clear the old position gdispFillArea(i, j, PIXMAP_WIDTH, PIXMAP_HEIGHT, Black); // Change the position i += PIXMAP_WIDTH/2; if (i >= width - PIXMAP_WIDTH/2) { i %= width - PIXMAP_WIDTH/2; j = (j + PIXMAP_HEIGHT/2) % (height - PIXMAP_HEIGHT/2); } // Blit the pixmap to the real display at the new position gdispBlitArea(i, j, PIXMAP_WIDTH, PIXMAP_HEIGHT, surface); // Wait gfxSleepMilliseconds(100); } // Clean up gdispPixmapDelete(pixmap); }
