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PNGDEC: Add crude cropping/scaling.
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@Gadgetoid
Gadgetoid committed Jul 21, 2023
1 parent 1630ddb commit 6db7a9a
Showing 1 changed file with 50 additions and 13 deletions.
63 changes: 50 additions & 13 deletions micropython/modules/pngdec/pngdec.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,8 @@ typedef struct _PNG_decode_target {
void *target;
uint8_t flags = 0;
Point position = {0, 0};
Rect source = {0, 0, 0, 0};
Point scale = {1, 1};
} _PNG_decode_target;

typedef struct _PNG_obj_t {
Expand Down Expand Up @@ -120,10 +122,15 @@ MICROPY_EVENT_POLL_HOOK
PicoGraphics *current_graphics = (PicoGraphics *)target->target;
Point current_position = target->position;
uint8_t current_flags = target->flags;
Point scale = target->scale;
// "pixel" is slow and clipped,
// guaranteeing we wont draw png data out of the framebuffer..
// Can we clip beforehand and make this faster?
current_position.y += pDraw->y;

if(pDraw->y < target->source.y || pDraw->y >= target->source.y + target->source.h) return;

current_position.y += pDraw->y * scale.y;
current_position -= Point(0, target->source.y);

//mp_printf(&mp_plat_print, "Drawing scanline at %d, %dbpp, type: %d, width: %d pitch: %d alpha: %d\n", y, pDraw->iBpp, pDraw->iPixelType, pDraw->iWidth, pDraw->iPitch, pDraw->iHasAlpha);
uint8_t *pixel = (uint8_t *)pDraw->pPixels;
Expand All @@ -132,21 +139,23 @@ MICROPY_EVENT_POLL_HOOK
uint8_t r = *pixel++;
uint8_t g = *pixel++;
uint8_t b = *pixel++;
if(x < target->source.x || x >= target->source.x + target->source.w) continue;
current_graphics->set_pen(r, g, b);
current_graphics->pixel(current_position);
current_position.x++;
current_graphics->rectangle({current_position.x, current_position.y, scale.x, scale.y});
current_position.x += scale.x;
}
} else if (pDraw->iPixelType == PNG_PIXEL_TRUECOLOR_ALPHA) {
for(int x = 0; x < pDraw->iWidth; x++) {
uint8_t r = *pixel++;
uint8_t g = *pixel++;
uint8_t b = *pixel++;
uint8_t a = *pixel++;
if(x < target->source.x || x >= target->source.x + target->source.w) continue;
if (a) {
current_graphics->set_pen(r, g, b);
current_graphics->pixel(current_position);
current_graphics->rectangle({current_position.x, current_position.y, scale.x, scale.y});
}
current_position.x++;
current_position.x += scale.x;
}
} else if (pDraw->iPixelType == PNG_PIXEL_INDEXED) {
for(int x = 0; x < pDraw->iWidth; x++) {
Expand All @@ -158,6 +167,7 @@ MICROPY_EVENT_POLL_HOOK
i >>= (x & 0b1) ? 0 : 4;
i &= 0xf;
}
if(x < target->source.x || x >= target->source.x + target->source.w) continue;
// grab the colour from the palette
uint8_t r = pDraw->pPalette[(i * 3) + 0];
uint8_t g = pDraw->pPalette[(i * 3) + 1];
Expand All @@ -168,10 +178,14 @@ MICROPY_EVENT_POLL_HOOK
if (current_flags & FLAG_NO_DITHER) {
// Posterized output to RGB332
current_graphics->set_pen(RGB(r, g, b).to_rgb332());
current_graphics->pixel(current_position);
current_graphics->rectangle({current_position.x, current_position.y, scale.x, scale.y});
} else {
// Dithered output to RGB332
current_graphics->set_pixel_dither(current_position, {r, g, b});
for(auto px = 0; px < scale.x; px++) {
for(auto py = 0; py < scale.y; py++) {
current_graphics->set_pixel_dither(current_position + Point{px, py}, {r, g, b});
}
}
}
} else if(current_graphics->pen_type == PicoGraphics::PEN_P8
|| current_graphics->pen_type == PicoGraphics::PEN_P4
Expand All @@ -184,17 +198,21 @@ MICROPY_EVENT_POLL_HOOK
closest = 0;
}
current_graphics->set_pen(closest);
current_graphics->pixel(current_position);
current_graphics->rectangle({current_position.x, current_position.y, scale.x, scale.y});
} else {
current_graphics->set_pixel_dither(current_position, {r, g, b});
}
for(auto px = 0; px < scale.x; px++) {
for(auto py = 0; py < scale.y; py++) {
current_graphics->set_pixel_dither(current_position + Point{px, py}, {r, g, b});
}
}
}

} else {
current_graphics->set_pen(r, g, b);
current_graphics->pixel(current_position);
current_graphics->rectangle({current_position.x, current_position.y, scale.x, scale.y});
}
}
current_position.x++;
current_position.x += scale.x;
}
}
}
Expand All @@ -215,6 +233,8 @@ mp_obj_t _PNG_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, co
self->base.type = &PNG_type;
self->png = m_new_class(PNG);

mp_printf(&mp_plat_print, "PNG RAM %fK\n", sizeof(PNG) / 1024.0f);

ModPicoGraphics_obj_t *graphics = (ModPicoGraphics_obj_t *)MP_OBJ_TO_PTR(args[ARG_picographics].u_obj);

self->decode_callback = PNGDraw;
Expand Down Expand Up @@ -265,13 +285,21 @@ mp_obj_t _PNG_openRAM(mp_obj_t self_in, mp_obj_t buffer) {

// decode
mp_obj_t _PNG_decode(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_self, ARG_x, ARG_y, ARG_scale, ARG_dither };
enum { ARG_self, ARG_x, ARG_y, ARG_scale, ARG_dither,
ARG_source_x, ARG_source_y, ARG_source_w, ARG_source_h,
ARG_scale_x, ARG_scale_y };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_x, MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_y, MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_scale, MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_dither, MP_ARG_OBJ, {.u_obj = mp_const_true} },
{ MP_QSTR_source_x, MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_source_y, MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_source_w, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_source_h, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_scale_x, MP_ARG_INT, {.u_int = 1} },
{ MP_QSTR_scale_y, MP_ARG_INT, {.u_int = 1} },
};

mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
Expand All @@ -293,6 +321,15 @@ mp_obj_t _PNG_decode(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args)

pngdec_open_helper(self);

int source_x = args[ARG_source_x].u_int;
int source_y = args[ARG_source_y].u_int;
int source_w = args[ARG_source_w].u_int == -1 ? self->width : args[ARG_source_w].u_int;
int source_h = args[ARG_source_h].u_int == -1 ? self->height : args[ARG_source_h].u_int;

self->decode_target->source = {source_x, source_y, source_w, source_h};

self->decode_target->scale = {args[ARG_scale_x].u_int, args[ARG_scale_y].u_int};

result = self->png->decode(self->decode_target, 0);

// Close the file since we've opened it on-demand
Expand Down

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